SSB1

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0003729 mRNA binding	IBA GO_REF:0000033	ACCEPT	Summary: mRNA binding is a core molecular function of Sbp1. CLIP analysis identified Sbp1 among P-body/stress-granule-associated RNA-binding proteins and showed it binds mRNAs with positional rather than strong sequence specificity, with a clear preference for the 5' UTR. The binding is mediated by its two RRM domains plus the RGG box. Reason: Core molecular function; well supported by phylogenetic inference and by direct CLIP evidence in S. cerevisiae. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits positional specificity on transcripts: Sbp1 binding shows a clear preference for the 5′ UTR, rather than strong sequence specificity
GO:0005634 nucleus	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Nuclear localization is phylogenetically inferred and is consistent only with the older nucleolar-form characterization of SSB1 (snR10/snR11-associated). The well-characterized contemporary function of Sbp1 is cytoplasmic; the falcon deep research synthesis does not support a nuclear site of action. Reason: Not supported by the contemporary cytoplasmic-function literature; retained as non-core given the historical nucleolar evidence and phylogenetic inference.
GO:0005737 cytoplasm	IBA GO_REF:0000033	ACCEPT	Summary: Cytoplasm is the constitutive subcellular location of Sbp1, consistent with its cytoplasmic mRNP/translation-control function and phylogenetic inference. Reason: Core, constitutive localization; consistent across phylogenetic inference and direct experimental evidence. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
GO:1990904 ribonucleoprotein complex	IBA GO_REF:0000033	ACCEPT	Summary: Sbp1 is a component of cytoplasmic messenger ribonucleoprotein (mRNP) complexes, consistent with its role in regulating mRNP state transitions between translation and translationally repressed/decay-competent states (P-bodies and stress granules). Reason: Supported by mRNP/CLIP studies placing Sbp1 within cytoplasmic mRNP complexes. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md SBP1 encodes an RGG/RRM RNA-binding protein that regulates cytoplasmic mRNP state transitions.
GO:0000932 P-body	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: Sbp1 accumulates in P-bodies under stress and upon overexpression, and is itself a P-body disassembly factor during recovery from stress. P-body localization is a genuine and functionally meaningful aspect of Sbp1 biology, though it is stress/condition-dependent rather than constitutive. Reason: Genuine but condition-dependent localization; central to Sbp1 function during stress recovery but not its constitutive site of action. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
GO:0003676 nucleic acid binding	IEA GO_REF:0000002	KEEP AS NON CORE	Summary: Generic nucleic-acid binding inferred from InterPro RRM-domain signatures. The activity is correct but the more specific child terms RNA binding (GO:0003723) and especially mRNA binding (GO:0003729) / mRNA 5'-UTR binding (GO:0048027) better capture the demonstrated function. Reason: Correct but uninformatively general; superseded by more specific RNA/mRNA binding annotations. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md describes the characteristic architecture of two RRMs separated by an RGG box
GO:0003723 RNA binding	IEA GO_REF:0000120	ACCEPT	Summary: RNA binding is well supported by Sbp1's two-RRM-plus-RGG architecture and by direct CLIP evidence. The more specific child term mRNA binding (GO:0003729) better captures the experimentally demonstrated activity, but this parent term is also correct. Reason: Correct; the more specific mRNA binding term is preferred where supported, but RNA binding is accurate. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md The literature synthesized here explicitly studies Saccharomyces cerevisiae Sbp1/Sbp1p (also referred to historically as Ssb1p) and describes the characteristic architecture of two RRMs separated by an RGG box
GO:0005730 nucleolus	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: Nucleolar localization (UniProt subcellular-location mapping) reflects the older SSB-1 characterization as a nucleolar snR10/snR11-associated protein. Distinct from the contemporary cytoplasmic mRNP/translation-control function; falcon synthesis does not address nucleolar localization. Reason: Historical nucleolar evidence separate from the well-characterized cytoplasmic function; retained as non-core.
GO:0005737 cytoplasm	IEA GO_REF:0000044	ACCEPT	Summary: Cytoplasm is the constitutive subcellular location of Sbp1, where it carries out its translation-repression function (UniProt subcellular-location mapping). Reason: Core, constitutive localization; well supported by experimental evidence. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
GO:0010494 cytoplasmic stress granule	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: Sbp1 localizes to cytoplasmic stress granules under stress and co-localizes with Dhh1 there. RRM1 (but not RRM2) is required for stress granule assembly. This is a genuine but stress-conditional localization. Reason: Genuine but condition-dependent localization rather than a constitutive site of action. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1’s CLIP target set was reported as most similar to Dhh1’s, and Sbp1 and Dhh1 were observed to co-localize in stress granules under stress
GO:0005515 protein binding	IPI PMID:16429126 Proteome survey reveals modularity of the yeast cell machine...	MARK AS OVER ANNOTATED	Summary: Generic protein binding from a high-throughput interactome survey. The biologically meaningful protein-protein interactions of Sbp1 are captured by more specific terms: eukaryotic initiation factor 4G binding (GO:0031370) and its interaction with the P-body component Edc3 underlying P-body disassembly. Reason: protein binding is uninformative; the specific eIF4G binding (GO:0031370) annotation already captures the functionally relevant interaction.
GO:0005515 protein binding	IPI PMID:16554755 Global landscape of protein complexes in the yeast Saccharom...	MARK AS OVER ANNOTATED	Summary: Generic protein binding from a high-throughput protein-complex survey. More specific terms (eIF4G binding, GO:0031370; and interaction with the P-body component Edc3) capture the functionally relevant interactions. Reason: protein binding is uninformative; the specific eIF4G binding (GO:0031370) annotation already captures the functionally relevant interaction.
GO:0005515 protein binding	IPI PMID:37968396 The social and structural architecture of the yeast protein ...	MARK AS OVER ANNOTATED	Summary: Generic protein binding from a yeast interactome study. The functionally relevant Sbp1 interactions are with eIF4G (GO:0031370) and with the P-body component Edc3 (the latter underlying Sbp1's P-body disassembly activity). Reason: protein binding is uninformative; the specific eIF4G binding (GO:0031370) annotation already captures the functionally relevant interaction.
GO:0045947 negative regulation of translational initiation	IDA PMID:28986506 Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- an...	ACCEPT	Summary: Negative regulation of translation initiation is a CORE function of Sbp1. It represses initiation by binding the scaffold factor eIF4G via its RGG motif, potentially destabilizing the eIF4E-eIF4G cap-binding complex and organizing a repressed mRNP. Overexpression of Sbp1 markedly reduces polysomes, consistent with repression of initiation. Reason: Direct experimental evidence establishes this as a core biological role of Sbp1; falcon synthesis elevates it from peripheral to core (revised from KEEP_AS_NON_CORE). Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md A central mechanistic concept for Sbp1 is repression of translation initiation by interaction with the scaffold initiation factor eIF4G, potentially destabilizing the eIF4E–eIF4G complex at the 5′ cap or organizing a repressed mRNP state
GO:0045947 negative regulation of translational initiation	IMP PMID:28986506 Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- an...	ACCEPT	Summary: Negative regulation of translation initiation is a CORE function of Sbp1, supported here by mutational/phenotypic (IMP) evidence (e.g. RGG- and poly(A)-dependent modulation of Pab1 mRNA translation). Repression operates through RGG-dependent eIF4G binding. Reason: Core biological role supported by direct mutant phenotype evidence; revised from KEEP_AS_NON_CORE based on falcon synthesis. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 is positioned in this regulatory space as (i) a translation repressor that can promote PB association and, more recently, (ii) a PB disassembly factor that promotes granule dissolution during recovery from stress
GO:0045947 negative regulation of translational initiation	IDA PMID:39617253 An Intrinsically Disordered RNA Binding Protein Modulates mR...	ACCEPT	Summary: Negative regulation of translation initiation is a CORE function of Sbp1. As an intrinsically disordered RGG/RRM RNA-binding protein it modulates mRNA translation and storage, repressing initiation through eIF4G engagement. Reason: Core biological role; revised from KEEP_AS_NON_CORE based on falcon synthesis and direct evidence. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers
GO:0045947 negative regulation of translational initiation	IMP PMID:39617253 An Intrinsically Disordered RNA Binding Protein Modulates mR...	ACCEPT	Summary: Negative regulation of translation initiation is a CORE function of Sbp1, supported by mutant phenotype (IMP) evidence. Repression of initiation through RGG-dependent eIF4G binding is the central mechanism. Reason: Core biological role supported by mutant phenotypes; revised from KEEP_AS_NON_CORE based on falcon synthesis. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md a translation repressor that can promote PB association and, more recently, (ii) a PB disassembly factor
GO:0048027 mRNA 5'-UTR binding	IDA PMID:28986506 Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- an...	ACCEPT	Summary: A precise, core molecular function: Sbp1 binds mRNAs with a clear positional preference for the 5' UTR (rather than strong sequence specificity), as shown by transcriptome-wide CLIP. This 5'-UTR occupancy is mechanistically consistent with its repression of cap-dependent initiation via eIF4G. Reason: Specific, experimentally supported molecular function central to Sbp1's role in translation control. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 binding shows a clear preference for the 5′ UTR, rather than strong sequence specificity
GO:0048027 mRNA 5'-UTR binding	IDA PMID:39617253 An Intrinsically Disordered RNA Binding Protein Modulates mR...	ACCEPT	Summary: Core molecular function: Sbp1 preferentially binds the 5' UTR of target mRNAs. Its positional 5'-binding preference is likely coupled to engagement of the 5'-end-associated factor eIF4G. Reason: Specific, experimentally supported molecular function central to Sbp1's role in translation control. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Positional preference likely linked to interaction with 5′-end-associated factor eIF4G
GO:0035617 stress granule disassembly	IDA PMID:35440550 Low complexity RGG-motif sequence is required for Processing...	MODIFY	Summary: Sbp1 is a granule DISASSEMBLY factor during recovery from stress. Roy et al. 2022 (PMID:35440550) is explicitly about PROCESSING BODY (P-body) disassembly: the title is "Low complexity RGG-motif sequence is required for Processing body (P-body) disassembly," and all three markers tested (Edc3, Dhh1, Scd6) are P-body components. After sodium-azide stress and recovery, delta-sbp1 cells are defective in disassembly of these P-body foci, and purified Sbp1 dissolves Edc3 assemblies in vitro in an RGG- and arginine-methylation-dependent manner. The annotated term GO:0035617 is STRESS GRANULE disassembly, a distinct GO process; the evidence supports P-body disassembly. There is no specific "P-body disassembly" / "processing body disassembly" term in GO (verified via OLS), so the closest accurate available term is GO:0032984 (protein-containing complex disassembly), which captures the demonstrated disaggregation of the P-body Edc3 protein assembly. Reason: The cited evidence (Roy et al. 2022, PMID:35440550) demonstrates P-body disassembly, not stress granule disassembly; GO:0035617 (stress granule disassembly) is the wrong process. No specific P-body/processing-body disassembly term exists in GO (confirmed via OLS - searches for "P-body disassembly" and "processing body disassembly" return no GO class), so the most accurate available replacement is GO:0032984 (protein-containing complex disassembly), matching the observed dissolution of Edc3 P-body assemblies. Proposed replacements: protein-containing complex disassembly Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md A major advance is the identification of Sbp1 as a PB disassembly factor during recovery from stress. Using sodium azide stress followed by recovery, Δsbp1 cells show defective disassembly (persistence) of PB foci marked by Edc3, Dhh1, and Scd6
GO:0000932 P-body	IDA PMID:23222640 Global analysis of yeast mRNPs.	KEEP AS NON CORE	Summary: Direct evidence places Sbp1 among P-body/stress-granule-associated RNA-binding proteins. P-body engagement is a genuine, functionally central but stress/condition-dependent aspect of Sbp1 biology (it both localizes to and promotes disassembly of P-bodies). Reason: Genuine condition-dependent localization; retained as non-core relative to the constitutive cytoplasmic site of action. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1)
GO:0010494 cytoplasmic stress granule	IDA PMID:23222640 Global analysis of yeast mRNPs.	KEEP AS NON CORE	Summary: Sbp1 localizes to cytoplasmic stress granules under stress, where it co-localizes with Dhh1; its CLIP target set is most similar to Dhh1's. Genuine but stress-conditional localization. Reason: Genuine but condition-dependent localization rather than a constitutive site of action. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 and Dhh1 were observed to co-localize in stress granules under stress
GO:0010494 cytoplasmic stress granule	HDA PMID:26777405 ATPase-Modulated Stress Granules Contain a Diverse Proteome ...	KEEP AS NON CORE	Summary: High-throughput proteomic identification of Sbp1 in stress granules, consistent with the focused microscopy showing stress-dependent Sbp1 stress-granule localization. Genuine but condition-dependent. Reason: Genuine but condition-dependent localization; consistent with focused studies. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1’s CLIP target set was reported as most similar to Dhh1’s, and Sbp1 and Dhh1 were observed to co-localize in stress granules under stress
GO:0003729 mRNA binding	HDA PMID:23222640 Global analysis of yeast mRNPs.	ACCEPT	Summary: mRNA binding is a core molecular function, directly demonstrated by CLIP in the Mitchell et al. global mRNP analysis, which mapped Sbp1's transcriptome-wide binding with a 5'-UTR positional preference. Reason: Core molecular function with direct transcriptome-wide binding evidence. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits positional specificity on transcripts: Sbp1 binding shows a clear preference for the 5′ UTR, rather than strong sequence specificity
GO:0003729 mRNA binding	IDA PMID:23222640 Global analysis of yeast mRNPs.	ACCEPT	Summary: mRNA binding is a core molecular function. Direct CLIP evidence shows Sbp1 binds mRNAs with positional (5'-UTR) rather than strong sequence specificity, mediated by its two RRMs and RGG box. Reason: Core molecular function with direct experimental support. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 binding shows a clear preference for the 5′ UTR, rather than strong sequence specificity
GO:0000932 P-body	IDA PMID:16782896 Sbp1p affects translational repression and decapping in Sacc...	KEEP AS NON CORE	Summary: Foundational evidence (Segal et al. 2006): Sbp1-GFP shows stress-dependent accumulation in P-bodies, and Sbp1 overexpression increases P-body localization/visibility of markers (e.g. Dhh1, Dcp2). Genuine but stress/overexpression-conditional localization. Reason: Genuine condition-dependent localization established in the foundational Segal 2006 study; non-core relative to the constitutive cytoplasmic site. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers
GO:0005730 nucleolus	IDA PMID:2121740 SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-s...	KEEP AS NON CORE	Summary: Nucleolar localization derives from the older characterization of "SSB-1" as a nucleolar-specific, silver-binding protein associated with the snR10 and snR11 small nuclear RNAs. This is a distinct, historical strand of evidence that the contemporary cytoplasmic mRNP/translation-control literature (and the falcon deep research synthesis) does not address. Retained as non-core pending reconciliation of the nucleolar and cytoplasmic bodies of evidence. Reason: Genuine IDA evidence from the original snRNA-association studies, but not part of the well-characterized contemporary cytoplasmic function; falcon synthesis does not address nucleolar localization.
GO:0005730 nucleolus	IDA PMID:2823109 Saccharomyces cerevisiae SSB1 protein and its relationship t...	KEEP AS NON CORE	Summary: Nucleolar localization from the original SSB1 characterization relating it to nucleolar RNA-binding proteins. Same caveat as the snR10/snR11 study: this historical nucleolar evidence is separate from the contemporary cytoplasmic mRNP/translation-control function and is not addressed by the falcon synthesis. Reason: Genuine historical IDA evidence, but not part of the well-characterized contemporary cytoplasmic function.
GO:0005737 cytoplasm	IDA PMID:16782896 Sbp1p affects translational repression and decapping in Sacc...	ACCEPT	Summary: Cytoplasm is the constitutive site of action for Sbp1. It is largely cytoplasmic in mid-log phase, where it carries out translational repression, relocalizing to P-bodies/stress granules only under stress. Reason: Core, constitutive subcellular localization where Sbp1 performs its translation-control function. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
GO:0017148 negative regulation of translation	IDA PMID:22284680 Scd6 targets eIF4G to repress translation: RGG motif protein...	ACCEPT	Summary: Negative regulation of translation is a CORE function. Rajyaguru et al. showed Sbp1 is one of a class of RGG-motif proteins that bind eIF4G to repress translation; the isolated Sbp1 RGG region (residues 121-180) is sufficient to bind GST-eIF4G. The more specific child term negative regulation of translational initiation (GO:0045947) is also annotated and preferred. Reason: Core biological role with direct biochemical evidence for the repression mechanism; revised from KEEP_AS_NON_CORE. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Biochemical evidence demonstrates that Sbp1 directly binds eIF4G, and that the RGG motif is required and sufficient for that interaction in vitro. In particular, an isolated Sbp1 RGG region (residues 121–180) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding
GO:0031370 eukaryotic initiation factor 4G binding	IDA PMID:22284680 Scd6 targets eIF4G to repress translation: RGG motif protein...	ACCEPT	Summary: eIF4G binding is a core, mechanistically central molecular function of Sbp1 and the direct biochemical basis of its translation-repression activity. The isolated RGG motif (residues 121-180) is required and sufficient to bind GST-eIF4G in vitro; deletion of the RGG region impairs binding. Reason: Core molecular function with direct in vitro binding evidence; this is the specific, informative interaction term that supersedes generic protein binding. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md an isolated Sbp1 RGG region (residues 121–180) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding
GO:0140311 protein sequestering activity	IDA PMID:35440550 Low complexity RGG-motif sequence is required for Processing...	NEW	Summary: NEW annotation capturing the molecular basis of Sbp1's P-body disassembly activity. Roy et al. 2022 (PMID:35440550) showed by binding studies with purified proteins that Sbp1 physically interacts with Edc3 and that the Sbp1-Edc3 interaction COMPETES with Edc3-Edc3 self-association; addition of purified Sbp1 (but not the RGG-deletion mutant) significantly decreases Edc3 assemblies. By binding Edc3 to prevent it from interacting with its self-assembly partners, Sbp1 exhibits protein sequestering activity, which is mechanistically distinct from its mRNA-binding/translation-repression functions. This term supersedes the generic protein binding (GO:0005515) annotations for the Edc3 interaction. Reason: Specific, informative MF (verified via OLS) capturing the RNA-independent Edc3-binding/disruption activity that underlies P-body disassembly; replaces uninformative protein binding for this interaction. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution
GO:0032055 negative regulation of translation in response to stress	IMP PMID:16782896 Sbp1p affects translational repression and decapping in Sacc...	KEEP AS NON CORE	Summary: Sbp1 represses translation and promotes P-body engagement particularly under stress conditions (e.g. glucose deprivation), consistent with a stress-responsive translational-repression role. This is a more contextualized child of the core negative-regulation-of-translation function. Reason: Valid stress-contextualized refinement of the core translational-repression role; kept as non-core relative to the general repression function. Supporting Evidence: file:yeast/SSB1/SSB1-deep-research-falcon.md Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers

Core Functions

Sbp1 binds the 5' UTR of target mRNAs via its two RRM domains and RGG box (positional rather than strong sequence specificity) and uses this RNA-binding activity, together with RGG-dependent binding to the scaffold initiation factor eIF4G, to repress cap-dependent translation initiation in the cytoplasm.

Molecular Function:

mRNA 5'-UTR binding

Directly Involved In:

negative regulation of translational initiation

Cellular Locations:

cytoplasm

Supporting Evidence:

file:yeast/SSB1/SSB1-deep-research-falcon.md
Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
file:yeast/SSB1/SSB1-deep-research-falcon.md
A central mechanistic concept for Sbp1 is repression of translation initiation by interaction with the scaffold initiation factor **eIF4G**, potentially destabilizing the eIF4E–eIF4G complex at the 5′ cap or organizing a repressed mRNP state

Sbp1 directly binds translation initiation factor eIF4G through its RGG motif (residues 121-180 required and sufficient in vitro), an interaction that is the biochemical basis of its translational-repression activity.

Molecular Function:

eukaryotic initiation factor 4G binding

Directly Involved In:

negative regulation of translation

Cellular Locations:

cytoplasm

Supporting Evidence:

file:yeast/SSB1/SSB1-deep-research-falcon.md
an isolated Sbp1 RGG region (residues **121–180**) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding

Under recovery from stress, Sbp1 acts as a P-body disassembly factor: it directly binds the P-body scaffold Edc3 in an RNA-independent manner (demonstrated by RNase-treated pull-downs), and the Sbp1-Edc3 interaction competes with Edc3-Edc3 self-association, dissolving Edc3/Dhh1/Scd6 foci in an RGG- and arginine-methylation-dependent manner. By sequestering Edc3 away from its self-assembly partners, Sbp1 promotes disaggregation of the P-body condensate. The molecular function here is protein sequestering (Edc3 binding/disruption), distinct from the mRNA-binding activity underlying translation repression.

Molecular Function:

protein sequestering activity

Directly Involved In:

protein-containing complex disassembly

Cellular Locations:

P-body cytoplasmic stress granule

Supporting Evidence:

file:yeast/SSB1/SSB1-deep-research-falcon.md
A major advance is the identification of Sbp1 as a **PB disassembly factor** during recovery from stress. Using sodium azide stress followed by recovery, Δsbp1 cells show defective disassembly (persistence) of PB foci marked by Edc3, Dhh1, and Scd6
file:yeast/SSB1/SSB1-deep-research-falcon.md
Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution
file:yeast/SSB1/SSB1-deep-research-falcon.md
Complementation and mutant analyses indicate that the **RGG motif is required** for rescuing PB disassembly defects, and an “arginine methylation defective” mutant (13 Arg→Ala in the RGG motif) fails to rescue, implicating arginine residues (and plausibly methylation state) in function

References

GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

GO_REF:0000033

Annotation inferences using phylogenetic trees

GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

PMID:16429126

Proteome survey reveals modularity of the yeast cell machinery.

PMID:16554755

Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.

PMID:16782896

Sbp1p affects translational repression and decapping in Saccharomyces cerevisiae.

PMID:2121740

SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-specific, silver-binding protein that is associated with the snR10 and snR11 small nuclear RNAs.

PMID:22284680

Scd6 targets eIF4G to repress translation: RGG motif proteins as a class of eIF4G-binding proteins.

PMID:23222640

Global analysis of yeast mRNPs.

PMID:26777405

ATPase-Modulated Stress Granules Contain a Diverse Proteome and Substructure.

PMID:2823109

Saccharomyces cerevisiae SSB1 protein and its relationship to nucleolar RNA-binding proteins.

PMID:28986506

Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner.

PMID:35440550

Low complexity RGG-motif sequence is required for Processing body (P-body) disassembly.

PMID:37968396

The social and structural architecture of the yeast protein interactome.

PMID:39617253

An Intrinsically Disordered RNA Binding Protein Modulates mRNA Translation and Storage.

file:yeast/SSB1/SSB1-deep-research-falcon.md

Falcon deep research report on SSB1/SBP1 (P10080, YHL034C)

Sbp1 (P10080, YHL034C; historical synonym SSB1/SSBR1) is an RGG/RRM RNA-binding protein with two RRM domains separated by an RGG box that regulates cytoplasmic mRNP state transitions between active translation and translationally repressed states associated with P-bodies and stress granules.

"The literature synthesized here explicitly studies *Saccharomyces cerevisiae* Sbp1/Sbp1p (also referred to historically as Ssb1p) and describes the characteristic architecture of **two RRMs separated by an RGG box**"
Sbp1 represses translation initiation by binding the scaffold factor eIF4G; the RGG motif (residues 121-180) is required and sufficient for the eIF4G interaction in vitro.

"Biochemical evidence demonstrates that Sbp1 **directly binds eIF4G**, and that the **RGG motif is required and sufficient** for that interaction in vitro. In particular, an isolated Sbp1 RGG region (residues **121–180**) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding"
Sbp1 binds mRNAs with a positional preference for the 5' UTR rather than strong sequence specificity, as shown by transcriptome-wide CLIP; its CLIP target set is most similar to Dhh1's.

"A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits **positional specificity** on transcripts: Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity"
Sbp1 is largely cytoplasmic in mid-log phase and accumulates in P-bodies and stress granules under stress conditions or upon overexpression, where overexpression reduces polysomes consistent with translational repression.

"Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling"
Sbp1 is a P-body DISASSEMBLY factor during recovery from stress: delta-sbp1 cells are defective in disassembly of Edc3-, Dhh1-, and Scd6-marked foci, and purified Sbp1 interacts with Edc3 and reduces Edc3 assemblies in vitro.

"Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution"
The RGG motif is required for Sbp1's P-body disassembly activity, and an arginine-methylation-defective mutant (13 Arg-to-Ala in the RGG motif) fails to rescue disassembly, implicating arginine residues and methylation state.

"Complementation and mutant analyses indicate that the **RGG motif is required** for rescuing PB disassembly defects, and an “arginine methylation defective” mutant (13 Arg→Ala in the RGG motif) fails to rescue, implicating arginine residues (and plausibly methylation state) in function"

Deep Research

Falcon

(SSB1-deep-research-falcon.md)

this with annotations you find in gene/protein databases, but these can be outdated or inaccurate. Falcon Edison Scientific Literature 15 citations 2 artifacts 2026-05-30T17:44:34.844806

Edison artifact artifact-00 (text/markdown)

## Context ID: pqac-00000012 The quantification of P-body disassembly defects in Δsbp1 cells for the markers Edc3, Dhh1, and Scd6 after sodium azide stress and (image/png)

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Research report: Saccharomyces cerevisiae SBP1 (YHL034C; UniProt P10080)

0) Target verification (gene/protein identity)

The literature synthesized here explicitly studies Saccharomyces cerevisiae Sbp1/Sbp1p (also referred to historically as Ssb1p) and describes the characteristic architecture of two RRMs separated by an RGG box, matching the UniProt P10080 description and yeast locus YHL034C (segal2006sbp1paffectstranslational pages 2-3, rajyaguru2012scd6targetseif4g pages 5-6).

1) Key concepts and definitions (current understanding)

SBP1 encodes an RGG/RRM RNA-binding protein that regulates cytoplasmic mRNP state transitions. In yeast, “mRNP state” is commonly framed as movement of mRNA between active translation and non-translating states that can be associated with P-bodies (PBs) and stress granules (SGs)—biomolecular condensates enriched for translation repression and decay factors. Sbp1 is positioned in this regulatory space as (i) a translation repressor that can promote PB association and, more recently, (ii) a PB disassembly factor that promotes granule dissolution during recovery from stress (segal2006sbp1paffectstranslational pages 8-10, roy2022lowcomplexityrggmotif pages 3-4).

Translation repression via initiation-factor targeting. A central mechanistic concept for Sbp1 is repression of translation initiation by interaction with the scaffold initiation factor eIF4G, potentially destabilizing the eIF4E–eIF4G complex at the 5′ cap or organizing a repressed mRNP state (segal2006sbp1paffectstranslational pages 10-11, rajyaguru2012scd6targetseif4g pages 5-6).

mRNA decapping pathway interface. PBs are enriched for the Dcp1/Dcp2 decapping enzyme and decapping activators such as Dhh1 and Pat1. Sbp1 is functionally linked to this system: overexpression can suppress decapping-mutant phenotypes and accelerate decapping of reporter transcripts in decapping-compromised backgrounds, while deletion alone does not produce strong baseline decay defects for standard reporters—suggesting Sbp1 modulates decapping conditionally and/or for subsets of mRNAs (segal2006sbp1paffectstranslational pages 5-6, segal2006sbp1paffectstranslational pages 10-11).

2) Molecular function: RNA binding and protein–protein interactions

2.1 RNA-binding properties and target positioning

A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits positional specificity on transcripts: Sbp1 binding shows a clear preference for the 5′ UTR, rather than strong sequence specificity (mitchell2013globalanalysisof pages 7-9). Sbp1’s CLIP target set was reported as most similar to Dhh1’s, and Sbp1 and Dhh1 were observed to co-localize in stress granules under stress (mitchell2013globalanalysisof pages 7-9).

2.2 Direct binding to translation initiation factor eIF4G (RGG-dependent)

Biochemical evidence demonstrates that Sbp1 directly binds eIF4G, and that the RGG motif is required and sufficient for that interaction in vitro. In particular, an isolated Sbp1 RGG region (residues 121–180) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding (rajyaguru2012scd6targetseif4g pages 5-6).

2.3 Interaction with PB component Edc3 and condensate regulation

Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution (roy2021rggmotifproteinsbp1 pages 7-10, roy2021rggmotifproteinsbp1 pages 26-29).

3) Cellular roles, localization, and pathway context

3.1 Translational repression and PB recruitment (foundational evidence)

Overexpression of Sbp1 produces strong evidence of translation repression and PB engagement:
- Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers (segal2006sbp1paffectstranslational pages 8-10).
- Under Sbp1 overexpression, Dhh1 localized to PBs in 80% of cells (n=78), whereas in glucose Dhh1 was diffuse and rarely in PBs in 90% of cells (n=40) (segal2006sbp1paffectstranslational pages 8-10).
- Dcp2-GFP PBs were described as small in 73% of cells (n=56) at baseline and showed increased PB localization in 79% of cells (n=67) when Sbp1 was overexpressed (segal2006sbp1paffectstranslational pages 8-10).

Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling (segal2006sbp1paffectstranslational pages 10-11).

3.2 Conditional modulation of decapping

Sbp1 overexpression partially compensates for decapping impairment:
- In a dcp2-7 mutant, overexpression shifted an MFA2pG reporter half-life from ~12 min to ~6 min, and in a dcp1-2 mutant the half-life was ~8 min upon Sbp1 overexpression (segal2006sbp1paffectstranslational pages 5-6).
- In contrast, deletion of SBP1 did not substantially change decay of MFA2pG or PGK1pG reporters in unstressed conditions, supporting a model where Sbp1 is not a universal basal decapping factor but can influence decapping depending on cellular context or transcript class (segal2006sbp1paffectstranslational pages 5-6, segal2006sbp1paffectstranslational pages 10-11).

Genetic interaction patterns further suggest Sbp1 functionally interfaces with canonical decapping activators (e.g., Pat1/Dhh1) in the transition of mRNAs from translation into decay-competent states (segal2006sbp1paffectstranslational pages 5-6, segal2006sbp1paffectstranslational pages 1-2).

3.3 PB disassembly factor (latest major gene-specific advance)

A major advance is the identification of Sbp1 as a PB disassembly factor during recovery from stress. Using sodium azide stress followed by recovery, Δsbp1 cells show defective disassembly (persistence) of PB foci marked by Edc3, Dhh1, and Scd6 (roy2022lowcomplexityrggmotif pages 3-4).

The associated quantification (foci per cell, mean ± SEM, n=4 independent experiments) and statistical support show significant recovery defects in Δsbp1, including:
- Edc3 disassembly defect (P=0.0002; and endogenously tagged Edc3 P=0.021) (roy2022lowcomplexityrggmotif media 205d9ed0, roy2022lowcomplexityrggmotif media 5a4ec429)
- Dhh1 disassembly defect (P=0.0125) (roy2022lowcomplexityrggmotif media eeac8fd2)
- Scd6 disassembly defect (P=0.0132) (roy2022lowcomplexityrggmotif media 743f1cb0)

Mechanistic requirement for the RGG motif and arginine methylation. Complementation and mutant analyses indicate that the RGG motif is required for rescuing PB disassembly defects, and an “arginine methylation defective” mutant (13 Arg→Ala in the RGG motif) fails to rescue, implicating arginine residues (and plausibly methylation state) in function (roy2021rggmotifproteinsbp1 pages 7-10).

4) Expert opinions and interpretive models (authoritative synthesis)

eIF4G as an integration hub for repression/decay factors. A synthesis by Rajyaguru & Parker frames Sbp1 as part of an RGG-motif protein class that binds eIF4G and modulates mRNA functional states. They highlight non-mutually exclusive models in which multiple RGG proteins may bind eIF4G simultaneously, act sequentially in time/space, or compete to specify distinct transcript subsets; they also emphasize post-translational modification (e.g., arginine methylation) as a potential regulator of these interactions (rajyaguru2012rggmotifproteins pages 4-5).

Positional binding as a driver of co-assembly. The CLIP-based analysis suggests that PB/SG mRNP composition may be governed not only by sequence-specific RNA binding but by positional binding preferences (Sbp1 at 5′ UTR; Pat1/Lsm1 near 3′ ends) and by protein–protein interactions (eIF4G–Sbp1), supporting a mechanistic logic for how translation initiation control could be coupled to decapping and deadenylation (mitchell2013globalanalysisof pages 7-9).

5) Current applications and real-world implementations

While SBP1 is not a therapeutic target, it has practical “real-world” use in yeast as a model system:
- Mechanistic dissection of condensate dynamics: SBP1 provides a genetically tractable example of a factor that promotes PB dissolution rather than assembly, useful for understanding recovery from stress and condensate homeostasis (roy2022lowcomplexityrggmotif pages 3-4, roy2022lowcomplexityrggmotif media 205d9ed0).
- Translation/decapping coupling experiments: Sbp1 overexpression and mutant backgrounds (dcp1/dcp2/pat1/dhh1) provide a toolkit for perturbing the translation-to-decay transition and measuring outcomes via polysome profiling, PB microscopy, and reporter half-life assays (segal2006sbp1paffectstranslational pages 8-10, segal2006sbp1paffectstranslational pages 5-6).
- 5′ UTR-centric mRNP targeting: Sbp1’s 5′ positional binding preference makes it a useful entry point for studying how 5′ UTR occupancy relates to initiation-factor engagement and downstream decapping competence (mitchell2013globalanalysisof pages 7-9, rajyaguru2012scd6targetseif4g pages 5-6).

6) Relevant statistics and data (selected highlights)

Key quantitative results supporting SBP1 functional annotation are consolidated in the table artifact below.

Functional role	Key experimental evidence/assay	Quantitative/conditional details	Domain/motif requirement	Primary source with DOI URL and publication date/year
Translation repression	Sbp1 overexpression reduced polysomes and promoted formation/localization of P-body markers, consistent with repression of translation initiation and mRNP remodeling (segal2006sbp1paffectstranslational pages 8-10, segal2006sbp1paffectstranslational pages 10-11)	Dhh1p localized to P-bodies in 80% of cells on Sbp1 overexpression (n=78); in glucose, Dhh1p was diffuse/rarely in P-bodies in 90% of cells (n=40). Dcp2p-GFP-marked P-bodies were small in 73% of cells at baseline (n=56) and increased on Sbp1 overexpression in 79% of cells (n=67) (segal2006sbp1paffectstranslational pages 8-10)	RGG box and RRMs are part of Sbp1 architecture; specific domain requirement for this phenotype not resolved in Segal 2006 (segal2006sbp1paffectstranslational pages 10-11, segal2006sbp1paffectstranslational pages 2-3)	Segal SP, Dunckley T, Parker R. Molecular and Cellular Biology (Jul 2006). DOI: https://doi.org/10.1128/MCB.01913-05 (segal2006sbp1paffectstranslational pages 8-10, segal2006sbp1paffectstranslational pages 10-11)
Decapping modulation	High-copy/overexpressed Sbp1 suppressed conditional decapping defects and accelerated decay of MFA2pG reporter in decapping mutants, indicating Sbp1 can enhance decapping under sensitized conditions (segal2006sbp1paffectstranslational pages 5-6, segal2006sbp1paffectstranslational pages 1-2)	MFA2pG half-life changed from ~12 min to ~6 min in dcp2-7 with Sbp1 overexpression and was ~8 min in dcp1-2 upon Sbp1 overexpression; effects were not due to altered deadenylation. sbp1Δ alone did not alter normal MFA2pG/PGK1pG decay (segal2006sbp1paffectstranslational pages 5-6)	No specific motif requirement established in this assay; mechanistic models implicate RNA-binding regions and eIF4E/eIF4G-associated functions (segal2006sbp1paffectstranslational pages 10-11)	Segal SP, Dunckley T, Parker R. Molecular and Cellular Biology (Jul 2006). DOI: https://doi.org/10.1128/MCB.01913-05 (segal2006sbp1paffectstranslational pages 5-6, segal2006sbp1paffectstranslational pages 10-11)
P-body localization	Fluorescence microscopy of SBP1-GFP showed stress-dependent accumulation in P-bodies; Sbp1 is cytoplasmic in log phase and relocalizes under glucose deprivation/high cell density or overexpression (segal2006sbp1paffectstranslational pages 10-11, segal2006sbp1paffectstranslational pages 1-2)	Localization occurs under stress rather than mid-log growth; overexpression increases P-body size/number and mRNA targeting to P-bodies (segal2006sbp1paffectstranslational pages 8-10, segal2006sbp1paffectstranslational pages 10-11)	Specific localization determinant not assigned in Segal 2006; later work links condensate behaviors to RGG motif-dependent functions (roy2021rggmotifproteinsbp1 pages 7-10)	Segal SP, Dunckley T, Parker R. Molecular and Cellular Biology (Jul 2006). DOI: https://doi.org/10.1128/MCB.01913-05 (segal2006sbp1paffectstranslational pages 8-10, segal2006sbp1paffectstranslational pages 10-11, segal2006sbp1paffectstranslational pages 1-2)
P-body disassembly	Live-cell microscopy after stress/recovery showed Δsbp1 cells are defective in disassembly of Edc3-, Dhh1-, and Scd6-marked P-bodies; complementation and in vitro reconstitution support Sbp1 as a disassembly factor (roy2021rggmotifproteinsbp1 pages 7-10, roy2022lowcomplexityrggmotif pages 3-4, roy2021rggmotifproteinsbp1 pages 26-29)	Stress: 0.5% sodium azide for 30 min at 30°C; recovery: 1 h. Quantified as foci/cell, mean ± SEM, n=4 independent experiments. Significant recovery defects in Δsbp1: Edc3 P=0.0002 (and endogenously tagged Edc3 P=0.021), Dhh1 P=0.0125, Scd6 P=0.0132 (roy2022lowcomplexityrggmotif pages 3-4, roy2022lowcomplexityrggmotif media 205d9ed0)	RGG motif required: SBP1ΔRGG fails to rescue; RGG motif necessary and sufficient to rescue PB disassembly defect. Arginine-methylation-defective mutant (13 Arg→Ala; AMD) also fails to rescue. RRM1, but not RRM2, required for stress granule assembly; deletion of either RRM did not affect Edc3 granule assembly/disassembly in the cited excerpt (roy2021rggmotifproteinsbp1 pages 7-10)	Roy R et al. Nature Communications (Apr 2022). DOI: https://doi.org/10.1038/s41467-022-29715-5 (roy2022lowcomplexityrggmotif pages 3-4, roy2022lowcomplexityrggmotif media 205d9ed0); Roy R et al. bioRxiv (Feb 2021). DOI: https://doi.org/10.1101/2021.02.23.432385 (roy2021rggmotifproteinsbp1 pages 7-10, roy2021rggmotifproteinsbp1 pages 26-29)
RNA-binding positional preference	CLIP analysis identified Sbp1-bound mRNAs and showed positional, not strong sequence, specificity; Sbp1-binding profiles are most similar to Dhh1 and enriched toward 5′ regions (mitchell2013globalanalysisof pages 7-9)	Sbp1 was one of four proteins (Pat1, Lsm1, Dhh1, Sbp1) profiled by CLIP. Study also noted 38% of identified mRNA-binding proteins changed localization during stress (global context for mRNP remodeling) (mitchell2013globalanalysisof pages 7-9)	Positional preference likely linked to interaction with 5′-end-associated factor eIF4G; no specific RRM/RGG requirement quantified in the excerpt (mitchell2013globalanalysisof pages 7-9)	Mitchell SF et al. Nature Structural & Molecular Biology (Dec 2013). DOI: https://doi.org/10.1038/nsmb.2468 (mitchell2013globalanalysisof pages 7-9)
eIF4G binding	In vitro binding/pulldown assays with recombinant proteins showed direct Sbp1-eIF4G interaction; isolated Sbp1 RGG region was sufficient to bind GST-eIF4G (rajyaguru2012scd6targetseif4g pages 5-6)	Isolated RGG motif (residues 121–180) interacted with GST-eIF4G but not GST alone; no Kd/affinity values reported in the excerpt (rajyaguru2012scd6targetseif4g pages 5-6)	RGG motif is required and sufficient for eIF4G binding in the cited assays (rajyaguru2012scd6targetseif4g pages 5-6)	Rajyaguru P, She M, Parker R. Molecular Cell (Jan 2012). DOI: https://doi.org/10.1016/j.molcel.2011.11.026 (rajyaguru2012scd6targetseif4g pages 5-6)
Edc3 interaction underlying disassembly	Purified-protein pulldowns and assembly assays showed direct Sbp1-Edc3 interaction and competition with Edc3 self-association, explaining Edc3 condensate dissolution (roy2021rggmotifproteinsbp1 pages 7-10, roy2021rggmotifproteinsbp1 pages 26-29)	Sbp1 bound Edc3 LSm-FDF and YjeF-N domains, but not FDF alone, in RNA-independent conditions (RNase A present). Addition of purified Sbp1 decreased Edc3 assemblies in vitro; no binding affinity constants provided (roy2021rggmotifproteinsbp1 pages 7-10, roy2021rggmotifproteinsbp1 pages 26-29)	RGG motif required for dissolution of Edc3 assemblies; AMD mutant defective, implicating arginine methylation in function (roy2021rggmotifproteinsbp1 pages 7-10)	Roy R et al. Nature Communications (Apr 2022). DOI: https://doi.org/10.1038/s41467-022-29715-5 (supported by bioRxiv precursor DOI https://doi.org/10.1101/2021.02.23.432385) (roy2021rggmotifproteinsbp1 pages 7-10, roy2021rggmotifproteinsbp1 pages 26-29)

Table: This table summarizes the main experimentally supported molecular and cellular functions of S. cerevisiae Sbp1/YHL034C, including translation repression, decapping modulation, RNA-binding properties, and roles in P-body dynamics. It highlights the assays, quantitative details, and motif/domain requirements most useful for a gene-function annotation report.

Figure-based quantitative evidence for PB disassembly defects in Δsbp1 (Edc3/Dhh1/Scd6) is available in Roy et al. 2022 (roy2022lowcomplexityrggmotif media 205d9ed0, roy2022lowcomplexityrggmotif media eeac8fd2, roy2022lowcomplexityrggmotif media 743f1cb0).

7) Recent developments (2023–2024)

In the retrieved and analyzed corpus, no SBP1-focused primary papers from 2023–2024 were recovered. The most recent SBP1-specific peer-reviewed advance available here is the 2022 study defining Sbp1 as an RGG-dependent PB disassembly factor and providing in vitro competition/assembly evidence with Edc3 (roy2022lowcomplexityrggmotif pages 3-4, roy2021rggmotifproteinsbp1 pages 7-10). A 2023 decapping review was retrieved, but Sbp1-specific evidence could not be extracted from its text via the evidence tool in this run, so it is not used to support gene-specific claims.

References (URLs and publication dates/years)

Segal SP, Dunckley T, Parker R. “Sbp1p affects translational repression and decapping in Saccharomyces cerevisiae.” Molecular and Cellular Biology (Jul 2006). https://doi.org/10.1128/MCB.01913-05 (segal2006sbp1paffectstranslational pages 8-10, segal2006sbp1paffectstranslational pages 5-6, segal2006sbp1paffectstranslational pages 10-11)
Rajyaguru P, She M, Parker R. “Scd6 targets eIF4G to repress translation: RGG motif proteins as a class of eIF4G-binding proteins.” Molecular Cell (Jan 2012). https://doi.org/10.1016/j.molcel.2011.11.026 (rajyaguru2012scd6targetseif4g pages 5-6)
Rajyaguru P, Parker R. “RGG motif proteins: Modulators of mRNA functional states.” Cell Cycle (Jan 2012). https://doi.org/10.4161/cc.20716 (rajyaguru2012rggmotifproteins pages 4-5)
Mitchell SF, Jain S, She M, Parker R. “Global analysis of yeast mRNPs.” Nature Structural & Molecular Biology (Dec 2013). https://doi.org/10.1038/nsmb.2468 (mitchell2013globalanalysisof pages 7-9)
Roy R, Das G, Kuttanda IA, Bhatter N, Rajyaguru PI. “Low complexity RGG-motif sequence is required for Processing body (P-body) disassembly.” Nature Communications (Apr 2022). https://doi.org/10.1038/s41467-022-29715-5 (roy2022lowcomplexityrggmotif pages 3-4, roy2022lowcomplexityrggmotif media 205d9ed0)
Roy R, Kuttanda IA, Bhatter N, Rajyaguru PI. “RGG-motif protein Sbp1 is required for Processing body (P-body) disassembly.” bioRxiv (Feb 2021). https://doi.org/10.1101/2021.02.23.432385 (roy2021rggmotifproteinsbp1 pages 7-10, roy2021rggmotifproteinsbp1 pages 26-29)

References

(segal2006sbp1paffectstranslational pages 2-3): Scott P. Segal, Travis Dunckley, and Roy Parker. Sbp1p affects translational repression and decapping in saccharomyces cerevisiae. Molecular and Cellular Biology, 26:5120-5130, Jul 2006. URL: https://doi.org/10.1128/mcb.01913-05, doi:10.1128/mcb.01913-05. This article has 72 citations and is from a domain leading peer-reviewed journal.
(rajyaguru2012scd6targetseif4g pages 5-6): Purusharth Rajyaguru, Meipei She, and Roy Parker. Scd6 targets eif4g to repress translation: rgg motif proteins as a class of eif4g-binding proteins. Molecular cell, 45 2:244-54, Jan 2012. URL: https://doi.org/10.1016/j.molcel.2011.11.026, doi:10.1016/j.molcel.2011.11.026. This article has 179 citations and is from a highest quality peer-reviewed journal.
(segal2006sbp1paffectstranslational pages 8-10): Scott P. Segal, Travis Dunckley, and Roy Parker. Sbp1p affects translational repression and decapping in saccharomyces cerevisiae. Molecular and Cellular Biology, 26:5120-5130, Jul 2006. URL: https://doi.org/10.1128/mcb.01913-05, doi:10.1128/mcb.01913-05. This article has 72 citations and is from a domain leading peer-reviewed journal.
(roy2022lowcomplexityrggmotif pages 3-4): Raju Roy, Gitartha Das, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I. Rajyaguru. Low complexity rgg-motif sequence is required for processing body (p-body) disassembly. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29715-5, doi:10.1038/s41467-022-29715-5. This article has 26 citations and is from a highest quality peer-reviewed journal.
(segal2006sbp1paffectstranslational pages 10-11): Scott P. Segal, Travis Dunckley, and Roy Parker. Sbp1p affects translational repression and decapping in saccharomyces cerevisiae. Molecular and Cellular Biology, 26:5120-5130, Jul 2006. URL: https://doi.org/10.1128/mcb.01913-05, doi:10.1128/mcb.01913-05. This article has 72 citations and is from a domain leading peer-reviewed journal.
(segal2006sbp1paffectstranslational pages 5-6): Scott P. Segal, Travis Dunckley, and Roy Parker. Sbp1p affects translational repression and decapping in saccharomyces cerevisiae. Molecular and Cellular Biology, 26:5120-5130, Jul 2006. URL: https://doi.org/10.1128/mcb.01913-05, doi:10.1128/mcb.01913-05. This article has 72 citations and is from a domain leading peer-reviewed journal.
(mitchell2013globalanalysisof pages 7-9): Sarah F Mitchell, Saumya Jain, Meipei She, and Roy Parker. Global analysis of yeast mrnps. Nature Structural & Molecular Biology, 20:127-133, Dec 2013. URL: https://doi.org/10.1038/nsmb.2468, doi:10.1038/nsmb.2468. This article has 435 citations and is from a highest quality peer-reviewed journal.
(roy2021rggmotifproteinsbp1 pages 7-10): Raju Roy, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I Rajyaguru. Rgg-motif protein sbp1 is required for processing body (p-body) disassembly. bioRxiv, Feb 2021. URL: https://doi.org/10.1101/2021.02.23.432385, doi:10.1101/2021.02.23.432385. This article has 0 citations.
(roy2021rggmotifproteinsbp1 pages 26-29): Raju Roy, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I Rajyaguru. Rgg-motif protein sbp1 is required for processing body (p-body) disassembly. bioRxiv, Feb 2021. URL: https://doi.org/10.1101/2021.02.23.432385, doi:10.1101/2021.02.23.432385. This article has 0 citations.
(segal2006sbp1paffectstranslational pages 1-2): Scott P. Segal, Travis Dunckley, and Roy Parker. Sbp1p affects translational repression and decapping in saccharomyces cerevisiae. Molecular and Cellular Biology, 26:5120-5130, Jul 2006. URL: https://doi.org/10.1128/mcb.01913-05, doi:10.1128/mcb.01913-05. This article has 72 citations and is from a domain leading peer-reviewed journal.
(roy2022lowcomplexityrggmotif media 205d9ed0): Raju Roy, Gitartha Das, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I. Rajyaguru. Low complexity rgg-motif sequence is required for processing body (p-body) disassembly. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29715-5, doi:10.1038/s41467-022-29715-5. This article has 26 citations and is from a highest quality peer-reviewed journal.
(roy2022lowcomplexityrggmotif media 5a4ec429): Raju Roy, Gitartha Das, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I. Rajyaguru. Low complexity rgg-motif sequence is required for processing body (p-body) disassembly. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29715-5, doi:10.1038/s41467-022-29715-5. This article has 26 citations and is from a highest quality peer-reviewed journal.
(roy2022lowcomplexityrggmotif media eeac8fd2): Raju Roy, Gitartha Das, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I. Rajyaguru. Low complexity rgg-motif sequence is required for processing body (p-body) disassembly. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29715-5, doi:10.1038/s41467-022-29715-5. This article has 26 citations and is from a highest quality peer-reviewed journal.
(roy2022lowcomplexityrggmotif media 743f1cb0): Raju Roy, Gitartha Das, Ishwarya Achappa Kuttanda, Nupur Bhatter, and Purusharth I. Rajyaguru. Low complexity rgg-motif sequence is required for processing body (p-body) disassembly. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29715-5, doi:10.1038/s41467-022-29715-5. This article has 26 citations and is from a highest quality peer-reviewed journal.
(rajyaguru2012rggmotifproteins pages 4-5): Purusharth Rajyaguru and Roy Parker. Rgg motif proteins: modulators of mrna functional states. Cell Cycle, 11:2594-2599, Jan 2012. URL: https://doi.org/10.4161/cc.20716, doi:10.4161/cc.20716. This article has 114 citations and is from a peer-reviewed journal.

Artifacts

Edison artifact artifact-00

Citations

mitchell2013globalanalysisof pages 7-9
roy2022lowcomplexityrggmotif pages 3-4
rajyaguru2012rggmotifproteins pages 4-5
https://doi.org/10.1128/MCB.01913-05
https://doi.org/10.1038/s41467-022-29715-5
https://doi.org/10.1101/2021.02.23.432385
https://doi.org/10.1038/nsmb.2468
https://doi.org/10.1016/j.molcel.2011.11.026
https://doi.org/10.4161/cc.20716
https://doi.org/10.1128/mcb.01913-05,
https://doi.org/10.1016/j.molcel.2011.11.026,
https://doi.org/10.1038/s41467-022-29715-5,
https://doi.org/10.1038/nsmb.2468,
https://doi.org/10.1101/2021.02.23.432385,
https://doi.org/10.4161/cc.20716,

📄 View Raw YAML

id: P10080
gene_symbol: SSB1
product_type: PROTEIN
status: IN_PROGRESS
taxon:
  id: NCBITaxon:559292
  label: Saccharomyces cerevisiae
description: |-
  NOTE ON IDENTITY: This entry (UniProt P10080, locus YHL034C) is the RGG/RRM
  RNA-binding protein commonly known as Sbp1p (gene SBP1; the symbol SSB1 / SSBR1
  is a historical synonym for THIS protein, and is distinct from the unrelated
  ribosome-associated Hsp70 chaperone Ssb1/Ssb2). Sbp1 is built from two RRM
  domains separated by a low-complexity RGG (Arg-Gly-Gly) box. Its core molecular
  function is sequence-non-specific binding of mRNA with a positional preference
  for the 5' UTR, coupled to RGG-dependent binding of the scaffold translation
  initiation factor eIF4G. Through eIF4G engagement Sbp1 acts as a translation
  repressor (negative regulation of translation initiation), promoting transition
  of mRNAs out of active translation. Sbp1 is predominantly cytoplasmic in log
  phase and relocalizes to P-bodies and stress granules under stress; it is a
  P-body DISASSEMBLY factor during recovery from stress, dissolving Edc3/Dhh1/Scd6
  foci in an RGG- and arginine-methylation-dependent manner. The older literature
  additionally reports a nucleolar, snR10/snR11-associated form, but the
  well-characterized contemporary function is cytoplasmic mRNP/translation control.
existing_annotations:
- term:
    id: GO:0003729
    label: mRNA binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      mRNA binding is a core molecular function of Sbp1. CLIP analysis identified Sbp1
      among P-body/stress-granule-associated RNA-binding proteins and showed it binds
      mRNAs with positional rather than strong sequence specificity, with a clear
      preference for the 5' UTR. The binding is mediated by its two RRM domains plus
      the RGG box.
    action: ACCEPT
    reason: Core molecular function; well supported by phylogenetic inference and by
      direct CLIP evidence in S. cerevisiae.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits **positional specificity** on transcripts: Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Nuclear localization is phylogenetically inferred and is consistent only with the
      older nucleolar-form characterization of SSB1 (snR10/snR11-associated). The
      well-characterized contemporary function of Sbp1 is cytoplasmic; the falcon deep
      research synthesis does not support a nuclear site of action.
    action: KEEP_AS_NON_CORE
    reason: Not supported by the contemporary cytoplasmic-function literature; retained
      as non-core given the historical nucleolar evidence and phylogenetic inference.
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Cytoplasm is the constitutive subcellular location of Sbp1, consistent with its
      cytoplasmic mRNP/translation-control function and phylogenetic inference.
    action: ACCEPT
    reason: Core, constitutive localization; consistent across phylogenetic inference
      and direct experimental evidence.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
- term:
    id: GO:1990904
    label: ribonucleoprotein complex
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: |-
      Sbp1 is a component of cytoplasmic messenger ribonucleoprotein (mRNP) complexes,
      consistent with its role in regulating mRNP state transitions between translation
      and translationally repressed/decay-competent states (P-bodies and stress
      granules).
    action: ACCEPT
    reason: Supported by mRNP/CLIP studies placing Sbp1 within cytoplasmic mRNP
      complexes.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        SBP1 encodes an RGG/RRM RNA-binding protein that regulates cytoplasmic mRNP state transitions.
- term:
    id: GO:0000932
    label: P-body
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: |-
      Sbp1 accumulates in P-bodies under stress and upon overexpression, and is itself
      a P-body disassembly factor during recovery from stress. P-body localization is
      a genuine and functionally meaningful aspect of Sbp1 biology, though it is
      stress/condition-dependent rather than constitutive.
    action: KEEP_AS_NON_CORE
    reason: Genuine but condition-dependent localization; central to Sbp1 function
      during stress recovery but not its constitutive site of action.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
- term:
    id: GO:0003676
    label: nucleic acid binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: |-
      Generic nucleic-acid binding inferred from InterPro RRM-domain signatures. The
      activity is correct but the more specific child terms RNA binding (GO:0003723)
      and especially mRNA binding (GO:0003729) / mRNA 5'-UTR binding (GO:0048027)
      better capture the demonstrated function.
    action: KEEP_AS_NON_CORE
    reason: Correct but uninformatively general; superseded by more specific RNA/mRNA
      binding annotations.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        describes the characteristic architecture of **two RRMs separated by an RGG box**
- term:
    id: GO:0003723
    label: RNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: |-
      RNA binding is well supported by Sbp1's two-RRM-plus-RGG architecture and by
      direct CLIP evidence. The more specific child term mRNA binding (GO:0003729)
      better captures the experimentally demonstrated activity, but this parent term
      is also correct.
    action: ACCEPT
    reason: Correct; the more specific mRNA binding term is preferred where supported,
      but RNA binding is accurate.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        The literature synthesized here explicitly studies *Saccharomyces cerevisiae* Sbp1/Sbp1p (also referred to historically as Ssb1p) and describes the characteristic architecture of **two RRMs separated by an RGG box**
- term:
    id: GO:0005730
    label: nucleolus
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: |-
      Nucleolar localization (UniProt subcellular-location mapping) reflects the older
      SSB-1 characterization as a nucleolar snR10/snR11-associated protein. Distinct
      from the contemporary cytoplasmic mRNP/translation-control function; falcon
      synthesis does not address nucleolar localization.
    action: KEEP_AS_NON_CORE
    reason: Historical nucleolar evidence separate from the well-characterized
      cytoplasmic function; retained as non-core.
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: |-
      Cytoplasm is the constitutive subcellular location of Sbp1, where it carries out
      its translation-repression function (UniProt subcellular-location mapping).
    action: ACCEPT
    reason: Core, constitutive localization; well supported by experimental evidence.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
- term:
    id: GO:0010494
    label: cytoplasmic stress granule
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: |-
      Sbp1 localizes to cytoplasmic stress granules under stress and co-localizes with
      Dhh1 there. RRM1 (but not RRM2) is required for stress granule assembly. This is
      a genuine but stress-conditional localization.
    action: KEEP_AS_NON_CORE
    reason: Genuine but condition-dependent localization rather than a constitutive
      site of action.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1’s CLIP target set was reported as most similar to Dhh1’s, and Sbp1 and Dhh1 were observed to co-localize in stress granules under stress
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:16429126
  review:
    summary: |-
      Generic protein binding from a high-throughput interactome survey. The
      biologically meaningful protein-protein interactions of Sbp1 are captured by
      more specific terms: eukaryotic initiation factor 4G binding (GO:0031370) and
      its interaction with the P-body component Edc3 underlying P-body disassembly.
    action: MARK_AS_OVER_ANNOTATED
    reason: protein binding is uninformative; the specific eIF4G binding (GO:0031370)
      annotation already captures the functionally relevant interaction.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:16554755
  review:
    summary: |-
      Generic protein binding from a high-throughput protein-complex survey. More
      specific terms (eIF4G binding, GO:0031370; and interaction with the P-body
      component Edc3) capture the functionally relevant interactions.
    action: MARK_AS_OVER_ANNOTATED
    reason: protein binding is uninformative; the specific eIF4G binding (GO:0031370)
      annotation already captures the functionally relevant interaction.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:37968396
  review:
    summary: |-
      Generic protein binding from a yeast interactome study. The functionally
      relevant Sbp1 interactions are with eIF4G (GO:0031370) and with the P-body
      component Edc3 (the latter underlying Sbp1's P-body disassembly activity).
    action: MARK_AS_OVER_ANNOTATED
    reason: protein binding is uninformative; the specific eIF4G binding (GO:0031370)
      annotation already captures the functionally relevant interaction.
- term:
    id: GO:0045947
    label: negative regulation of translational initiation
  evidence_type: IDA
  original_reference_id: PMID:28986506
  review:
    summary: |-
      Negative regulation of translation initiation is a CORE function of Sbp1. It
      represses initiation by binding the scaffold factor eIF4G via its RGG motif,
      potentially destabilizing the eIF4E-eIF4G cap-binding complex and organizing a
      repressed mRNP. Overexpression of Sbp1 markedly reduces polysomes, consistent
      with repression of initiation.
    action: ACCEPT
    reason: Direct experimental evidence establishes this as a core biological role of
      Sbp1; falcon synthesis elevates it from peripheral to core (revised from
      KEEP_AS_NON_CORE).
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        A central mechanistic concept for Sbp1 is repression of translation initiation by interaction with the scaffold initiation factor **eIF4G**, potentially destabilizing the eIF4E–eIF4G complex at the 5′ cap or organizing a repressed mRNP state
- term:
    id: GO:0045947
    label: negative regulation of translational initiation
  evidence_type: IMP
  original_reference_id: PMID:28986506
  review:
    summary: |-
      Negative regulation of translation initiation is a CORE function of Sbp1,
      supported here by mutational/phenotypic (IMP) evidence (e.g. RGG- and
      poly(A)-dependent modulation of Pab1 mRNA translation). Repression operates
      through RGG-dependent eIF4G binding.
    action: ACCEPT
    reason: Core biological role supported by direct mutant phenotype evidence; revised
      from KEEP_AS_NON_CORE based on falcon synthesis.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 is positioned in this regulatory space as (i) a translation repressor that can promote PB association and, more recently, (ii) a PB **disassembly factor** that promotes granule dissolution during recovery from stress
- term:
    id: GO:0045947
    label: negative regulation of translational initiation
  evidence_type: IDA
  original_reference_id: PMID:39617253
  review:
    summary: |-
      Negative regulation of translation initiation is a CORE function of Sbp1. As an
      intrinsically disordered RGG/RRM RNA-binding protein it modulates mRNA
      translation and storage, repressing initiation through eIF4G engagement.
    action: ACCEPT
    reason: Core biological role; revised from KEEP_AS_NON_CORE based on falcon
      synthesis and direct evidence.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers
- term:
    id: GO:0045947
    label: negative regulation of translational initiation
  evidence_type: IMP
  original_reference_id: PMID:39617253
  review:
    summary: |-
      Negative regulation of translation initiation is a CORE function of Sbp1,
      supported by mutant phenotype (IMP) evidence. Repression of initiation through
      RGG-dependent eIF4G binding is the central mechanism.
    action: ACCEPT
    reason: Core biological role supported by mutant phenotypes; revised from
      KEEP_AS_NON_CORE based on falcon synthesis.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        a translation repressor that can promote PB association and, more recently, (ii) a PB **disassembly factor**
- term:
    id: GO:0048027
    label: mRNA 5'-UTR binding
  evidence_type: IDA
  original_reference_id: PMID:28986506
  review:
    summary: |-
      A precise, core molecular function: Sbp1 binds mRNAs with a clear positional
      preference for the 5' UTR (rather than strong sequence specificity), as shown by
      transcriptome-wide CLIP. This 5'-UTR occupancy is mechanistically consistent with
      its repression of cap-dependent initiation via eIF4G.
    action: ACCEPT
    reason: Specific, experimentally supported molecular function central to Sbp1's
      role in translation control.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
- term:
    id: GO:0048027
    label: mRNA 5'-UTR binding
  evidence_type: IDA
  original_reference_id: PMID:39617253
  review:
    summary: |-
      Core molecular function: Sbp1 preferentially binds the 5' UTR of target mRNAs.
      Its positional 5'-binding preference is likely coupled to engagement of the
      5'-end-associated factor eIF4G.
    action: ACCEPT
    reason: Specific, experimentally supported molecular function central to Sbp1's
      role in translation control.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Positional preference likely linked to interaction with 5′-end-associated factor eIF4G
- term:
    id: GO:0035617
    label: stress granule disassembly
  evidence_type: IDA
  original_reference_id: PMID:35440550
  review:
    summary: |-
      Sbp1 is a granule DISASSEMBLY factor during recovery from stress. Roy et al. 2022
      (PMID:35440550) is explicitly about PROCESSING BODY (P-body) disassembly: the
      title is "Low complexity RGG-motif sequence is required for Processing body
      (P-body) disassembly," and all three markers tested (Edc3, Dhh1, Scd6) are P-body
      components. After sodium-azide stress and recovery, delta-sbp1 cells are defective
      in disassembly of these P-body foci, and purified Sbp1 dissolves Edc3 assemblies
      in vitro in an RGG- and arginine-methylation-dependent manner. The annotated term
      GO:0035617 is STRESS GRANULE disassembly, a distinct GO process; the evidence
      supports P-body disassembly. There is no specific "P-body disassembly" /
      "processing body disassembly" term in GO (verified via OLS), so the closest
      accurate available term is GO:0032984 (protein-containing complex disassembly),
      which captures the demonstrated disaggregation of the P-body Edc3 protein assembly.
    action: MODIFY
    reason: The cited evidence (Roy et al. 2022, PMID:35440550) demonstrates P-body
      disassembly, not stress granule disassembly; GO:0035617 (stress granule
      disassembly) is the wrong process. No specific P-body/processing-body disassembly
      term exists in GO (confirmed via OLS - searches for "P-body disassembly" and
      "processing body disassembly" return no GO class), so the most accurate available
      replacement is GO:0032984 (protein-containing complex disassembly), matching the
      observed dissolution of Edc3 P-body assemblies.
    proposed_replacement_terms:
    - id: GO:0032984
      label: protein-containing complex disassembly
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        A major advance is the identification of Sbp1 as a **PB disassembly factor** during recovery from stress. Using sodium azide stress followed by recovery, Δsbp1 cells show defective disassembly (persistence) of PB foci marked by Edc3, Dhh1, and Scd6
- term:
    id: GO:0000932
    label: P-body
  evidence_type: IDA
  original_reference_id: PMID:23222640
  review:
    summary: |-
      Direct evidence places Sbp1 among P-body/stress-granule-associated RNA-binding
      proteins. P-body engagement is a genuine, functionally central but
      stress/condition-dependent aspect of Sbp1 biology (it both localizes to and
      promotes disassembly of P-bodies).
    action: KEEP_AS_NON_CORE
    reason: Genuine condition-dependent localization; retained as non-core relative to
      the constitutive cytoplasmic site of action.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1)
- term:
    id: GO:0010494
    label: cytoplasmic stress granule
  evidence_type: IDA
  original_reference_id: PMID:23222640
  review:
    summary: |-
      Sbp1 localizes to cytoplasmic stress granules under stress, where it co-localizes
      with Dhh1; its CLIP target set is most similar to Dhh1's. Genuine but
      stress-conditional localization.
    action: KEEP_AS_NON_CORE
    reason: Genuine but condition-dependent localization rather than a constitutive
      site of action.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 and Dhh1 were observed to co-localize in stress granules under stress
- term:
    id: GO:0010494
    label: cytoplasmic stress granule
  evidence_type: HDA
  original_reference_id: PMID:26777405
  review:
    summary: |-
      High-throughput proteomic identification of Sbp1 in stress granules, consistent
      with the focused microscopy showing stress-dependent Sbp1 stress-granule
      localization. Genuine but condition-dependent.
    action: KEEP_AS_NON_CORE
    reason: Genuine but condition-dependent localization; consistent with focused
      studies.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1’s CLIP target set was reported as most similar to Dhh1’s, and Sbp1 and Dhh1 were observed to co-localize in stress granules under stress
- term:
    id: GO:0003729
    label: mRNA binding
  evidence_type: HDA
  original_reference_id: PMID:23222640
  review:
    summary: |-
      mRNA binding is a core molecular function, directly demonstrated by CLIP in the
      Mitchell et al. global mRNP analysis, which mapped Sbp1's transcriptome-wide
      binding with a 5'-UTR positional preference.
    action: ACCEPT
    reason: Core molecular function with direct transcriptome-wide binding evidence.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits **positional specificity** on transcripts: Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
- term:
    id: GO:0003729
    label: mRNA binding
  evidence_type: IDA
  original_reference_id: PMID:23222640
  review:
    summary: |-
      mRNA binding is a core molecular function. Direct CLIP evidence shows Sbp1 binds
      mRNAs with positional (5'-UTR) rather than strong sequence specificity, mediated
      by its two RRMs and RGG box.
    action: ACCEPT
    reason: Core molecular function with direct experimental support.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
- term:
    id: GO:0000932
    label: P-body
  evidence_type: IDA
  original_reference_id: PMID:16782896
  review:
    summary: |-
      Foundational evidence (Segal et al. 2006): Sbp1-GFP shows stress-dependent
      accumulation in P-bodies, and Sbp1 overexpression increases P-body
      localization/visibility of markers (e.g. Dhh1, Dcp2). Genuine but
      stress/overexpression-conditional localization.
    action: KEEP_AS_NON_CORE
    reason: Genuine condition-dependent localization established in the foundational
      Segal 2006 study; non-core relative to the constitutive cytoplasmic site.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers
- term:
    id: GO:0005730
    label: nucleolus
  evidence_type: IDA
  original_reference_id: PMID:2121740
  review:
    summary: |-
      Nucleolar localization derives from the older characterization of "SSB-1" as a
      nucleolar-specific, silver-binding protein associated with the snR10 and snR11
      small nuclear RNAs. This is a distinct, historical strand of evidence that the
      contemporary cytoplasmic mRNP/translation-control literature (and the falcon deep
      research synthesis) does not address. Retained as non-core pending reconciliation
      of the nucleolar and cytoplasmic bodies of evidence.
    action: KEEP_AS_NON_CORE
    reason: Genuine IDA evidence from the original snRNA-association studies, but not
      part of the well-characterized contemporary cytoplasmic function; falcon
      synthesis does not address nucleolar localization.
- term:
    id: GO:0005730
    label: nucleolus
  evidence_type: IDA
  original_reference_id: PMID:2823109
  review:
    summary: |-
      Nucleolar localization from the original SSB1 characterization relating it to
      nucleolar RNA-binding proteins. Same caveat as the snR10/snR11 study: this
      historical nucleolar evidence is separate from the contemporary cytoplasmic
      mRNP/translation-control function and is not addressed by the falcon synthesis.
    action: KEEP_AS_NON_CORE
    reason: Genuine historical IDA evidence, but not part of the well-characterized
      contemporary cytoplasmic function.
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IDA
  original_reference_id: PMID:16782896
  review:
    summary: |-
      Cytoplasm is the constitutive site of action for Sbp1. It is largely cytoplasmic
      in mid-log phase, where it carries out translational repression, relocalizing to
      P-bodies/stress granules only under stress.
    action: ACCEPT
    reason: Core, constitutive subcellular localization where Sbp1 performs its
      translation-control function.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
- term:
    id: GO:0017148
    label: negative regulation of translation
  evidence_type: IDA
  original_reference_id: PMID:22284680
  review:
    summary: |-
      Negative regulation of translation is a CORE function. Rajyaguru et al. showed
      Sbp1 is one of a class of RGG-motif proteins that bind eIF4G to repress
      translation; the isolated Sbp1 RGG region (residues 121-180) is sufficient to
      bind GST-eIF4G. The more specific child term negative regulation of translational
      initiation (GO:0045947) is also annotated and preferred.
    action: ACCEPT
    reason: Core biological role with direct biochemical evidence for the repression
      mechanism; revised from KEEP_AS_NON_CORE.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Biochemical evidence demonstrates that Sbp1 **directly binds eIF4G**, and that the **RGG motif is required and sufficient** for that interaction in vitro. In particular, an isolated Sbp1 RGG region (residues **121–180**) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding
- term:
    id: GO:0031370
    label: eukaryotic initiation factor 4G binding
  evidence_type: IDA
  original_reference_id: PMID:22284680
  review:
    summary: |-
      eIF4G binding is a core, mechanistically central molecular function of Sbp1 and
      the direct biochemical basis of its translation-repression activity. The isolated
      RGG motif (residues 121-180) is required and sufficient to bind GST-eIF4G in
      vitro; deletion of the RGG region impairs binding.
    action: ACCEPT
    reason: Core molecular function with direct in vitro binding evidence; this is the
      specific, informative interaction term that supersedes generic protein binding.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        an isolated Sbp1 RGG region (residues **121–180**) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding
- term:
    id: GO:0140311
    label: protein sequestering activity
  evidence_type: IDA
  original_reference_id: PMID:35440550
  review:
    summary: |-
      NEW annotation capturing the molecular basis of Sbp1's P-body disassembly
      activity. Roy et al. 2022 (PMID:35440550) showed by binding studies with purified
      proteins that Sbp1 physically interacts with Edc3 and that the Sbp1-Edc3
      interaction COMPETES with Edc3-Edc3 self-association; addition of purified Sbp1
      (but not the RGG-deletion mutant) significantly decreases Edc3 assemblies. By
      binding Edc3 to prevent it from interacting with its self-assembly partners, Sbp1
      exhibits protein sequestering activity, which is mechanistically distinct from its
      mRNA-binding/translation-repression functions. This term supersedes the generic
      protein binding (GO:0005515) annotations for the Edc3 interaction.
    action: NEW
    reason: Specific, informative MF (verified via OLS) capturing the RNA-independent
      Edc3-binding/disruption activity that underlies P-body disassembly; replaces
      uninformative protein binding for this interaction.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution
- term:
    id: GO:0032055
    label: negative regulation of translation in response to stress
  evidence_type: IMP
  original_reference_id: PMID:16782896
  review:
    summary: |-
      Sbp1 represses translation and promotes P-body engagement particularly under
      stress conditions (e.g. glucose deprivation), consistent with a stress-responsive
      translational-repression role. This is a more contextualized child of the core
      negative-regulation-of-translation function.
    action: KEEP_AS_NON_CORE
    reason: Valid stress-contextualized refinement of the core translational-repression
      role; kept as non-core relative to the general repression function.
    additional_reference_ids:
    - file:yeast/SSB1/SSB1-deep-research-falcon.md
    supported_by:
    - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
      supporting_text: |-
        Sbp1 overexpression markedly reduces polysomes, consistent with translational repression, and increases PB localization/visibility of PB markers
core_functions:
- description: |-
    Sbp1 binds the 5' UTR of target mRNAs via its two RRM domains and RGG box (positional
    rather than strong sequence specificity) and uses this RNA-binding activity, together
    with RGG-dependent binding to the scaffold initiation factor eIF4G, to repress
    cap-dependent translation initiation in the cytoplasm.
  molecular_function:
    id: GO:0048027
    label: mRNA 5'-UTR binding
  directly_involved_in:
  - id: GO:0045947
    label: negative regulation of translational initiation
  locations:
  - id: GO:0005737
    label: cytoplasm
  supported_by:
  - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
    supporting_text: |-
      Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
  - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
    supporting_text: |-
      A central mechanistic concept for Sbp1 is repression of translation initiation by interaction with the scaffold initiation factor **eIF4G**, potentially destabilizing the eIF4E–eIF4G complex at the 5′ cap or organizing a repressed mRNP state
- description: |-
    Sbp1 directly binds translation initiation factor eIF4G through its RGG motif
    (residues 121-180 required and sufficient in vitro), an interaction that is the
    biochemical basis of its translational-repression activity.
  molecular_function:
    id: GO:0031370
    label: eukaryotic initiation factor 4G binding
  directly_involved_in:
  - id: GO:0017148
    label: negative regulation of translation
  locations:
  - id: GO:0005737
    label: cytoplasm
  supported_by:
  - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
    supporting_text: |-
      an isolated Sbp1 RGG region (residues **121–180**) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding
- description: |-
    Under recovery from stress, Sbp1 acts as a P-body disassembly factor: it directly
    binds the P-body scaffold Edc3 in an RNA-independent manner (demonstrated by
    RNase-treated pull-downs), and the Sbp1-Edc3 interaction competes with Edc3-Edc3
    self-association, dissolving Edc3/Dhh1/Scd6 foci in an RGG- and
    arginine-methylation-dependent manner. By sequestering Edc3 away from its
    self-assembly partners, Sbp1 promotes disaggregation of the P-body condensate. The
    molecular function here is protein sequestering (Edc3 binding/disruption), distinct
    from the mRNA-binding activity underlying translation repression.
  molecular_function:
    id: GO:0140311
    label: protein sequestering activity
  directly_involved_in:
  - id: GO:0032984
    label: protein-containing complex disassembly
  locations:
  - id: GO:0000932
    label: P-body
  - id: GO:0010494
    label: cytoplasmic stress granule
  supported_by:
  - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
    supporting_text: |-
      A major advance is the identification of Sbp1 as a **PB disassembly factor** during recovery from stress. Using sodium azide stress followed by recovery, Δsbp1 cells show defective disassembly (persistence) of PB foci marked by Edc3, Dhh1, and Scd6
  - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
    supporting_text: |-
      Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution
  - reference_id: file:yeast/SSB1/SSB1-deep-research-falcon.md
    supporting_text: |-
      Complementation and mutant analyses indicate that the **RGG motif is required** for rescuing PB disassembly defects, and an “arginine methylation defective” mutant (13 Arg→Ala in the RGG motif) fails to rescue, implicating arginine residues (and plausibly methylation state) in function
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:16429126
  title: Proteome survey reveals modularity of the yeast cell machinery.
  findings: []
- id: PMID:16554755
  title: Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.
  findings: []
- id: PMID:16782896
  title: Sbp1p affects translational repression and decapping in Saccharomyces cerevisiae.
  findings: []
- id: PMID:2121740
  title: SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-specific, silver-binding protein that is associated with the snR10 and snR11 small nuclear RNAs.
  findings: []
- id: PMID:22284680
  title: 'Scd6 targets eIF4G to repress translation: RGG motif proteins as a class of eIF4G-binding proteins.'
  findings: []
- id: PMID:23222640
  title: Global analysis of yeast mRNPs.
  findings: []
- id: PMID:26777405
  title: ATPase-Modulated Stress Granules Contain a Diverse Proteome and Substructure.
  findings: []
- id: PMID:2823109
  title: Saccharomyces cerevisiae SSB1 protein and its relationship to nucleolar RNA-binding proteins.
  findings: []
- id: PMID:28986506
  title: Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner.
  findings: []
- id: PMID:35440550
  title: Low complexity RGG-motif sequence is required for Processing body (P-body) disassembly.
  findings: []
- id: PMID:37968396
  title: The social and structural architecture of the yeast protein interactome.
  findings: []
- id: PMID:39617253
  title: An Intrinsically Disordered RNA Binding Protein Modulates mRNA Translation and Storage.
  findings: []
- id: file:yeast/SSB1/SSB1-deep-research-falcon.md
  title: Falcon deep research report on SSB1/SBP1 (P10080, YHL034C)
  findings:
  - statement: |
      Sbp1 (P10080, YHL034C; historical synonym SSB1/SSBR1) is an RGG/RRM RNA-binding
      protein with two RRM domains separated by an RGG box that regulates cytoplasmic
      mRNP state transitions between active translation and translationally repressed
      states associated with P-bodies and stress granules.
    supporting_text: |-
      The literature synthesized here explicitly studies *Saccharomyces cerevisiae* Sbp1/Sbp1p (also referred to historically as Ssb1p) and describes the characteristic architecture of **two RRMs separated by an RGG box**
    reference_section_type: OTHER
  - statement: |
      Sbp1 represses translation initiation by binding the scaffold factor eIF4G;
      the RGG motif (residues 121-180) is required and sufficient for the eIF4G
      interaction in vitro.
    supporting_text: |-
      Biochemical evidence demonstrates that Sbp1 **directly binds eIF4G**, and that the **RGG motif is required and sufficient** for that interaction in vitro. In particular, an isolated Sbp1 RGG region (residues **121–180**) bound GST-eIF4G in binding assays, whereas deletion of the RGG region impaired binding
    reference_section_type: OTHER
  - statement: |
      Sbp1 binds mRNAs with a positional preference for the 5' UTR rather than strong
      sequence specificity, as shown by transcriptome-wide CLIP; its CLIP target set is
      most similar to Dhh1's.
    supporting_text: |-
      A global yeast mRNP study using CLIP identified Sbp1 among a set of PB/SG-associated RBPs (with Pat1, Lsm1, Dhh1) and found that Sbp1 exhibits **positional specificity** on transcripts: Sbp1 binding shows a clear preference for the **5′ UTR**, rather than strong sequence specificity
    reference_section_type: OTHER
  - statement: |
      Sbp1 is largely cytoplasmic in mid-log phase and accumulates in P-bodies and
      stress granules under stress conditions or upon overexpression, where
      overexpression reduces polysomes consistent with translational repression.
    supporting_text: |-
      Sbp1 itself is largely cytoplasmic in mid-log phase and accumulates in PBs under stress conditions (e.g., glucose deprivation/high cell density) or upon overexpression, consistent with conditional relocalization during mRNP remodeling
    reference_section_type: OTHER
  - statement: |
      Sbp1 is a P-body DISASSEMBLY factor during recovery from stress: delta-sbp1 cells
      are defective in disassembly of Edc3-, Dhh1-, and Scd6-marked foci, and purified
      Sbp1 interacts with Edc3 and reduces Edc3 assemblies in vitro.
    supporting_text: |-
      Recent work supporting a PB disassembly role shows that purified Sbp1 can interact with Edc3 domains (LSm-FDF and YjeF-N in the cited excerpt), in RNase-treated conditions (supporting RNA-independent detectability), and that Sbp1 can reduce Edc3 assemblies in vitro—supporting a mechanistic basis for PB dissolution
    reference_section_type: OTHER
  - statement: |
      The RGG motif is required for Sbp1's P-body disassembly activity, and an
      arginine-methylation-defective mutant (13 Arg-to-Ala in the RGG motif) fails to
      rescue disassembly, implicating arginine residues and methylation state.
    supporting_text: |-
      Complementation and mutant analyses indicate that the **RGG motif is required** for rescuing PB disassembly defects, and an “arginine methylation defective” mutant (13 Arg→Ala in the RGG motif) fails to rescue, implicating arginine residues (and plausibly methylation state) in function
    reference_section_type: OTHER

Gene Description

Existing Annotations Review

Core Functions

Sbp1 directly binds translation initiation factor eIF4G through its RGG motif (residues 121-180 required and sufficient in vitro), an interaction that is the biochemical basis of its translational-repression activity.

References

Deep Research

Falcon

Research report: Saccharomyces cerevisiae SBP1 (YHL034C; UniProt P10080)

0) Target verification (gene/protein identity)

1) Key concepts and definitions (current understanding)

2) Molecular function: RNA binding and protein–protein interactions

2.1 RNA-binding properties and target positioning

2.2 Direct binding to translation initiation factor eIF4G (RGG-dependent)

2.3 Interaction with PB component Edc3 and condensate regulation

3) Cellular roles, localization, and pathway context

3.1 Translational repression and PB recruitment (foundational evidence)

3.2 Conditional modulation of decapping

3.3 PB disassembly factor (latest major gene-specific advance)

4) Expert opinions and interpretive models (authoritative synthesis)

5) Current applications and real-world implementations

6) Relevant statistics and data (selected highlights)

7) Recent developments (2023–2024)

References (URLs and publication dates/years)

Artifacts

Citations

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