pnut

UniProt ID: P40797
Organism: Drosophila melanogaster
Review Status: COMPLETE
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Gene Description

Peanut (Pnut) is the Drosophila SEPT7-class septin, a filament-forming GTPase that is the shared central subunit of both fly septin hetero-oligomers, Sep1-Sep2-Pnut and Sep4-Sep5-Pnut. Purified from embryos as a complex with Sep1 and Sep2, it binds and hydrolyses GTP and polymerises into filaments, a process stimulated by Orc6 binding to the Pnut coiled-coil. Pnut localizes to the cell cortex, the cleavage furrow, the contractile ring and the intercellular bridge, and is required for cytokinesis of proliferating cells; pnut mutant imaginal tissues become multinucleate. Septin complexes containing Pnut bind, bundle and bend actin filaments into curved rings, organising actomyosin rings during cellularization, cytokinesis and single-cell wound repair, and also contribute to border cell migration and other cortical processes.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0000281 mitotic cytokinesis
IDA
PMID:40171709
Septin complexes: Ahead of the curve.
ACCEPT
Summary: Pnut is required for cytokinesis of proliferating cells.
Reason: pnut mutant imaginal tissues form large multinucleate cells, and Peanut knockdown causes cytokinesis failure; Pnut is the shared SEPT7-class subunit of both septin complexes. Core process.
Supporting Evidence:
PMID:8181057
We find that pnut is also required for cytokinesis
GO:0000281 mitotic cytokinesis
IMP
PMID:26853367
Cell Competition Drives the Formation of Metastatic Tumors i...
ACCEPT
Summary: Pnut is required for cytokinesis of proliferating cells.
Reason: pnut mutant imaginal tissues form large multinucleate cells, and Peanut knockdown causes cytokinesis failure; Pnut is the shared SEPT7-class subunit of both septin complexes. Core process.
Supporting Evidence:
PMID:26853367
Cytokinesis failure due to downregulation of Peanut is required for tumorigenesis.
GO:0000281 mitotic cytokinesis
IMP
PMID:29719260
Yorkie and JNK Control Tumorigenesis in Drosophila Cells wit...
ACCEPT
Summary: Pnut is required for cytokinesis of proliferating cells.
Reason: pnut mutant imaginal tissues form large multinucleate cells, and Peanut knockdown causes cytokinesis failure; Pnut is the shared SEPT7-class subunit of both septin complexes. Core process.
Supporting Evidence:
PMID:8181057
We find that pnut is also required for cytokinesis
GO:0000281 mitotic cytokinesis
IMP
PMID:8181057
The Drosophila peanut gene is required for cytokinesis and e...
ACCEPT
Summary: Pnut is required for cytokinesis of proliferating cells.
Reason: pnut mutant imaginal tissues form large multinucleate cells, and Peanut knockdown causes cytokinesis failure; Pnut is the shared SEPT7-class subunit of both septin complexes. Core process.
Supporting Evidence:
PMID:8181057
We find that pnut is also required for cytokinesis
GO:0003779 actin binding
IDA
PMID:11076973
Lava lamp, a novel peripheral golgi protein, is required for...
MODIFY
Summary: Pnut recovered in a biochemical screen for microfilament/microtubule-associated proteins.
Reason: Generic parent of GO:0051015 actin filament binding, which Pnut already carries with stronger direct evidence (PMID:38728140): purified septins bind and bundle actin filaments. The general term is correct but less specific than the evidence supports, so replace it with the more specific term the gene already carries.
Proposed replacements: actin filament binding
Supporting Evidence:
PMID:38728140
Strikingly, we find that all five Drosophila Septins can bind to and bundle actin filaments
GO:0003924 GTPase activity
IBA
GO_REF:0000033
ACCEPT
Summary: Septin GTPase activity inherited from the septin family node.
Reason: IBA from PANTHER node PTN000430171 (donors include Pnut, Sep1, yeast Cdc3/Cdc12 and human SEPTIN4). The gene itself has direct experimental support (IDA).
Supporting Evidence:
PMID:25355953
We show that Drosophila septin complex functions depend on the intact GTP-binding and/or hydrolysis domains of Pnut, Sep1, and Sep2.
GO:0003924 GTPase activity
IDA
PMID:18987337
Drosophila Orc6 facilitates GTPase activity and filament for...
ACCEPT
Summary: Septin complex binds and hydrolyses GTP; this subunit carries catalytic activity.
Reason: Direct biochemical evidence: the Pnut-Sep2-Sep1 complex hydrolyses GTP, and mutational analysis shows complex function depends on intact GTP-binding/hydrolysis domains of Pnut and Sep1 (Sep2 alone is inactive). GTP hydrolysis is a core intrinsic activity of this septin subunit.
Supporting Evidence:
PMID:18987337
the binding of Orc6 to Pnut increases the intrinsic GTPase activity of the Drosophila septin complex
GO:0003924 GTPase activity
IDA
PMID:25355953
Functional insight into the role of Orc6 in septin complex f...
ACCEPT
Summary: Septin complex binds and hydrolyses GTP; this subunit carries catalytic activity.
Reason: Direct biochemical evidence: the Pnut-Sep2-Sep1 complex hydrolyses GTP, and mutational analysis shows complex function depends on intact GTP-binding/hydrolysis domains of Pnut and Sep1 (Sep2 alone is inactive). GTP hydrolysis is a core intrinsic activity of this septin subunit.
Supporting Evidence:
PMID:25355953
We show that Drosophila septin complex functions depend on the intact GTP-binding and/or hydrolysis domains of Pnut, Sep1, and Sep2.
GO:0003924 GTPase activity
IDA
PMID:8636235
A purified Drosophila septin complex forms filaments and exh...
ACCEPT
Summary: Septin complex binds and hydrolyses GTP; this subunit carries catalytic activity.
Reason: Direct biochemical evidence: the Pnut-Sep2-Sep1 complex hydrolyses GTP, and mutational analysis shows complex function depends on intact GTP-binding/hydrolysis domains of Pnut and Sep1 (Sep2 alone is inactive). GTP hydrolysis is a core intrinsic activity of this septin subunit.
Supporting Evidence:
PMID:8636235
It binds and hydrolyzes exogenously added GTP.
GO:0005515 protein binding
IPI
PMID:11884525
Identification of septin-interacting proteins and characteri...
REMOVE
Summary: Two-hybrid interaction with a SUMO-pathway protein.
Reason: Generic protein binding from a yeast two-hybrid screen for septin-interacting proteins (PMID:11884525) is uninformative and there is no specific binding term that captures the reported interactor; removal per curation policy on protein binding.
GO:0005515 protein binding
IPI
PMID:15818553
D-Hillarin, a novel W180-domain protein, affects cytokinesis...
REMOVE
Summary: Co-immunoprecipitation of Pnut with D-Hillarin.
Reason: Generic protein binding is uninformative. The interaction with the W180-domain protein D-Hillarin is from cross-immunoprecipitation only, and no more specific binding term describes it.
GO:0005525 GTP binding
IDA
PMID:25355953
Functional insight into the role of Orc6 in septin complex f...
ACCEPT
Summary: Septin subunits copurify with bound guanine nucleotide and bind GTP.
Reason: Direct evidence that the septin complex and its subunits bind guanine nucleotide; GTP binding is the defining biochemical property of the septin GTPase fold.
Supporting Evidence:
PMID:25355953
We show that Drosophila septin complex functions depend on the intact GTP-binding and/or hydrolysis domains of Pnut, Sep1, and Sep2.
GO:0005525 GTP binding
IEA
GO_REF:0000002
ACCEPT
Summary: GTP binding predicted from the septin-type G domain.
Reason: Septins bind guanine nucleotide stably; the purified Drosophila complex copurifies with one bound guanine nucleotide per subunit. This holds even for the SEPT6-class subunits (Sep2/Sep5), which bind but do not exchange or hydrolyse GTP.
Supporting Evidence:
PMID:8636235
The complex copurifies with one molecule of bound guanine nucleotide per septin polypeptide.
GO:0005737 cytoplasm
IEA
GO_REF:0000117
MODIFY
Summary: Septins are cytoplasmic proteins that assemble at the cortex.
Reason: Correct but general; this septin is a subunit of a hetero-oligomeric septin complex, and the gene already carries the more specific cytoplasmic term GO:0031105 septin complex (a descendant of cytoplasm).
Proposed replacements: septin complex
Supporting Evidence:
PMID:38728140
Taken together, our findings further suggest that Sep1/Sep2/Pnut and Sep4/Sep5/Pnut are functioning as distinct complexes within the context of cell wound repair.
GO:0005856 cytoskeleton
IEA
GO_REF:0000117
MODIFY
Summary: Septins are components of the cytoskeleton.
Reason: Correct but general; septin hetero-oligomers form the septin cytoskeleton, and the gene already carries the more specific term GO:0031105 septin complex (a descendant of cytoskeleton).
Proposed replacements: septin complex
Supporting Evidence:
PMID:38728140
Taken together, our findings further suggest that Sep1/Sep2/Pnut and Sep4/Sep5/Pnut are functioning as distinct complexes within the context of cell wound repair.
GO:0005886 plasma membrane
IDA
PMID:18987337
Drosophila Orc6 facilitates GTPase activity and filament for...
ACCEPT
Summary: Pnut and the septin complex associate with the plasma membrane.
Reason: Pnut is detected at cell membranes in the embryo; Rho activity recruits septins to membranes. Cortical membrane association is part of septin function.
Supporting Evidence:
PMID:29079679
All Pnut variants were detected at cell membranes during interphase, and at the cleavage furrow between dividing cells.
GO:0005886 plasma membrane
IDA
PMID:29079679
Phosphorylation of Pnut in the Early Stages of Drosophila Em...
ACCEPT
Summary: Pnut and the septin complex associate with the plasma membrane.
Reason: Pnut is detected at cell membranes in the embryo; Rho activity recruits septins to membranes. Cortical membrane association is part of septin function.
Supporting Evidence:
PMID:29079679
All Pnut variants were detected at cell membranes during interphase, and at the cleavage furrow between dividing cells.
GO:0005938 cell cortex
IEA
GO_REF:0000044
ACCEPT
Summary: Pnut localizes to the cell cortex.
Reason: Pnut localizes to cell membranes/cortex during interphase and to the cleavage furrow during division.
Supporting Evidence:
PMID:29079679
All Pnut variants were detected at cell membranes during interphase, and at the cleavage furrow between dividing cells.
GO:0005940 septin ring
IBA
GO_REF:0000033
ACCEPT
Summary: Septin ring localization inherited from the septin family.
Reason: IBA from PANTHER node PTN000430171 with broad fungal, mammalian, worm and Drosophila donors. Drosophila septins form ring structures at the cleavage furrow and around cell wounds.
Supporting Evidence:
PMID:8181057
Pnut protein is localized to the cleavage furrow of dividing cells during cytokinesis and to the intercellular bridge connecting postmitotic daughter cells.
GO:0005940 septin ring
IPI
PMID:40171709
Septin complexes: Ahead of the curve.
ACCEPT
Summary: Septins assemble into ring structures at the wound edge and division site.
Reason: Curator annotation from the Nakamura and Parkhurst review, which describes septin complexes organised as rings at the wound edge; Drosophila septins also form rings at the cleavage furrow.
Supporting Evidence:
PMID:40171709
Taken together, our study demonstrated that the bending of actin filaments by two distinct Septin complexes regulates the assembly and disassembly of the actomyosin ring during cell wound repair
GO:0006915 apoptotic process
IGI
PMID:15029247
The mitochondrial ARTS protein promotes apoptosis through ta...
KEEP AS NON CORE
Summary: pnut mutations dominantly suppress Reaper/Hid/Grim-induced cell killing.
Reason: IGI with rpr, hid and grim: reduced pnut dosage suppresses RHG-induced death in the eye, consistent with Pnut being related to the pro-apoptotic mammalian SEPTIN4 isoform ARTS. A modifier role, not a core septin function.
Supporting Evidence:
PMID:15029247
mutations in peanut, which encodes a Drosophila homologue of ARTS, can dominantly suppress cell killing by Reaper, Hid and Grim
GO:0006915 apoptotic process
IGI
PMID:15029247
The mitochondrial ARTS protein promotes apoptosis through ta...
KEEP AS NON CORE
Summary: pnut mutations dominantly suppress Reaper/Hid/Grim-induced cell killing.
Reason: IGI with rpr, hid and grim: reduced pnut dosage suppresses RHG-induced death in the eye, consistent with Pnut being related to the pro-apoptotic mammalian SEPTIN4 isoform ARTS. A modifier role, not a core septin function.
Supporting Evidence:
PMID:15029247
mutations in peanut, which encodes a Drosophila homologue of ARTS, can dominantly suppress cell killing by Reaper, Hid and Grim
GO:0006915 apoptotic process
IGI
PMID:15029247
The mitochondrial ARTS protein promotes apoptosis through ta...
KEEP AS NON CORE
Summary: pnut mutations dominantly suppress Reaper/Hid/Grim-induced cell killing.
Reason: IGI with rpr, hid and grim: reduced pnut dosage suppresses RHG-induced death in the eye, consistent with Pnut being related to the pro-apoptotic mammalian SEPTIN4 isoform ARTS. A modifier role, not a core septin function.
Supporting Evidence:
PMID:15029247
mutations in peanut, which encodes a Drosophila homologue of ARTS, can dominantly suppress cell killing by Reaper, Hid and Grim
GO:0007298 border follicle cell migration
IMP
PMID:37329886
Septins regulate border cell surface geometry, shape, and mo...
KEEP AS NON CORE
Summary: Septins regulate border cell cluster shape and motility.
Reason: RNAi against Sep1, Sep2 or Pnut impairs border cell migration; septins act downstream of Rho to tune cluster surface deformability. Developmental, context-specific role; non-core.
Supporting Evidence:
PMID:37329886
Expressing RNAi against Sep1, Sep2, or Pnut impaired migration (Figures 2B–2D).
GO:0007349 cellularization
TAS
PMID:12386932
How one becomes many: blastoderm cellularization in Drosophi...
KEEP AS NON CORE
Summary: Septins localise to the cellularization front.
Reason: TAS from a review of blastoderm cellularization. Septins concentrate at the leading edge of cellularization furrows and the septin complex was purified from cellularizing embryos; cellularization is a specialised cytokinesis, retained as non-core.
Supporting Evidence:
PMID:11076973
Seven (Anillin, KLP3A, Dynamin A and B, Peanut, Septin 1, and Septin 2) have been previously implicated in cellularization and/or cytokinesis, suggesting that the screen has enriched for the desired class of proteins.
GO:0007476 imaginal disc-derived wing morphogenesis
IMP
PMID:34496252
Atypical laminin spots and pull-generated microtubule-actin ...
KEEP AS NON CORE
Summary: Septins required for microtubule-actin cables that mediate wing surface adhesion.
Reason: IMP from a study of wing adhesion during metamorphosis, in which septins are needed to form pressure-resistant microtubule-actin projections. Tissue-level morphogenesis that likely reflects the general septin role in cortical cytoskeletal organisation; non-core.
Supporting Evidence:
PMID:34496252
Formation of cables resistant to pressure requires spectraplakin, Patronin, septins, and Sdb
GO:0008017 microtubule binding
IDA
PMID:11076973
Lava lamp, a novel peripheral golgi protein, is required for...
KEEP AS NON CORE
Summary: Pnut co-purifies with microtubules in an MMAP affinity screen.
Reason: The evidence is co-purification with microtubule/actin-associated proteins from embryo extracts, which may be indirect (septins associate with many MAPs). Septin-microtubule association is documented in other systems, but the core cytoskeletal activity of Drosophila septins is actin filament binding/bending.
Supporting Evidence:
PMID:11076973
Seven (Anillin, KLP3A, Dynamin A and B, Peanut, Septin 1, and Septin 2) have been previously implicated in cellularization and/or cytokinesis, suggesting that the screen has enriched for the desired class of proteins.
GO:0008104 intracellular protein localization
IBA
GO_REF:0000033
KEEP AS NON CORE
Summary: Septin scaffolds localise other proteins to the cell cortex.
Reason: IBA from PANTHER node PTN000430171 with fungal donors (yeast Shs1/Cdc11, Candida septins) and human SEPTIN14, where septin collars restrict and recruit proteins. Plausible for Drosophila septin scaffolds but not directly shown for this gene; retained as non-core.
GO:0015630 microtubule cytoskeleton
IBA
GO_REF:0000033
KEEP AS NON CORE
Summary: Septin association with microtubules inherited from mammalian/yeast septins.
Reason: IBA from PANTHER node PTN000430171 with donors including human SEPTIN2, SEPTIN7, SEPTIN9 and SEPTIN12. Septins do associate with microtubules in some cell types, and Drosophila Pnut/Sep1/Sep2 were recovered in a microtubule/microfilament-associated protein screen, but the primary Drosophila septin structures are cortical and actin-associated. Basis: phylogenetic inference only; no cached Drosophila paper directly shows this septin on microtubules.
GO:0016324 apical plasma membrane
EXP
PMID:8181057
The Drosophila peanut gene is required for cytokinesis and e...
KEEP AS NON CORE
Summary: Pnut found at the apical membrane in some epithelial contexts.
Reason: The cited study reports Pnut at the cleavage furrow and intercellular bridge; apical membrane localization is a context-dependent subset of its cortical localization. Retained as non-core.
GO:0016324 apical plasma membrane
IEA
GO_REF:0000044
KEEP AS NON CORE
Summary: Pnut found at the apical membrane in some epithelial contexts.
Reason: The cited study reports Pnut at the cleavage furrow and intercellular bridge; apical membrane localization is a context-dependent subset of its cortical localization. Retained as non-core.
GO:0031105 septin complex
IBA
GO_REF:0000033
ACCEPT
Summary: Septin complex membership inherited across the septin family.
Reason: IBA from PANTHER node PTN000430171 with very broad donors, including all Drosophila septins in the curated set. Experimental evidence confirms membership of this subunit in a hetero-oligomeric septin complex.
Supporting Evidence:
PMID:38728140
Taken together, our findings further suggest that Sep1/Sep2/Pnut and Sep4/Sep5/Pnut are functioning as distinct complexes within the context of cell wound repair.
GO:0031105 septin complex
IDA
PMID:18987337
Drosophila Orc6 facilitates GTPase activity and filament for...
ACCEPT
Summary: Subunit of the hetero-oligomeric septin complex.
Reason: Direct biochemical evidence that this subunit assembles into a hetero-oligomeric septin complex (Sep1/Sep2/Pnut and/or Sep4/Sep5/Pnut). Core location.
Supporting Evidence:
PMID:18987337
Septin complex was purified from Drosophila embryos and also reconstituted from recombinant proteins.
GO:0031105 septin complex
IGI
PMID:37329886
Septins regulate border cell surface geometry, shape, and mo...
ACCEPT
Summary: Subunit of the hetero-oligomeric septin complex.
Reason: IGI: Sep1 or Sep2 knockdown reduces Pnut protein levels in follicle cells, consistent with mutual stabilisation within a complex. Membership is independently established biochemically (PMID:8636235).
Supporting Evidence:
PMID:37329886
Expressing RNAi against Sep1, Sep2, or Pnut impaired migration (Figures 2B–2D).
PMID:8636235
The purified complex is comprised of the three previously identified septin polypeptides Pnut, Sep2, and Sep1.
GO:0031105 septin complex
IPI
PMID:24633326
Septins promote F-actin ring formation by crosslinking actin...
ACCEPT
Summary: Subunit of the hetero-oligomeric septin complex.
Reason: IPI (curator-supplied; abstract-only cache): septins were studied as a complex bundling actin into rings during cellularization. Membership of Pnut, Sep1 and Sep2 in one complex is independently established by immunopurification (PMID:8636235).
Supporting Evidence:
PMID:24633326
In vitro reconstitution assays show that septins alone bundle actin filaments into rings
PMID:8636235
The purified complex is comprised of the three previously identified septin polypeptides Pnut, Sep2, and Sep1.
GO:0031105 septin complex
IPI
PMID:25355953
Functional insight into the role of Orc6 in septin complex f...
ACCEPT
Summary: Subunit of the hetero-oligomeric septin complex.
Reason: Direct biochemical evidence that this subunit assembles into a hetero-oligomeric septin complex (Sep1/Sep2/Pnut and/or Sep4/Sep5/Pnut). Core location.
Supporting Evidence:
PMID:25355953
We reconstituted a recombinant Drosophila septin complex and compared activities of the wild-type and several mutant septin complex variants both in vitro and in vivo.
GO:0031105 septin complex
IPI
PMID:8636235
A purified Drosophila septin complex forms filaments and exh...
ACCEPT
Summary: Subunit of the hetero-oligomeric septin complex.
Reason: Direct biochemical evidence that this subunit assembles into a hetero-oligomeric septin complex (Sep1/Sep2/Pnut and/or Sep4/Sep5/Pnut). Core location.
Supporting Evidence:
PMID:8636235
The purified complex is comprised of the three previously identified septin polypeptides Pnut, Sep2, and Sep1.
GO:0031105 septin complex
TAS
PMID:38728140
Two Septin complexes mediate actin dynamics during cell woun...
ACCEPT
Summary: Subunit of the hetero-oligomeric septin complex.
Reason: Direct biochemical evidence that this subunit assembles into a hetero-oligomeric septin complex (Sep1/Sep2/Pnut and/or Sep4/Sep5/Pnut). Core location.
Supporting Evidence:
PMID:38728140
Taken together, our findings further suggest that Sep1/Sep2/Pnut and Sep4/Sep5/Pnut are functioning as distinct complexes within the context of cell wound repair.
GO:0031625 ubiquitin protein ligase binding
IPI
PMID:17456438
Drosophila melanogaster Parkin ubiquitinates peanut and sept...
KEEP AS NON CORE
Summary: Septin interacts with, and is ubiquitinated by, the E3 ligase Parkin.
Reason: Pnut and Sep1 are substrates of Parkin E3 ligase activity; binding the ligase is a property of a substrate, not a function the septin performs. Informative binding term, retained as non-core.
Supporting Evidence:
PMID:17456438
peanut and septin1, D. melanogaster septin proteins, were also ubiquitinated by D. melanogaster Parkin
GO:0032153 cell division site
IBA
GO_REF:0000033
MODIFY
Summary: Septins accumulate at the cell division site.
Reason: IBA from PANTHER node PTN000430171 with broad donors. Correct but general: direct immunolocalization places this septin at the cleavage furrow, and the gene already carries the more specific child term GO:0032154 cleavage furrow.
Proposed replacements: cleavage furrow
Supporting Evidence:
PMID:8181057
Pnut protein is localized to the cleavage furrow of dividing cells during cytokinesis and to the intercellular bridge connecting postmitotic daughter cells.
GO:0032154 cleavage furrow
IDA
PMID:10485851
A putative exchange factor for Rho1 GTPase is required for i...
ACCEPT
Summary: Septin localizes to the cleavage furrow during cytokinesis.
Reason: Septins are recruited to the cleavage furrow of dividing cells; direct immunolocalization in multiple Drosophila cell types. Core location for the cytokinetic role.
Supporting Evidence:
PMID:8181057
Pnut protein is localized to the cleavage furrow of dividing cells during cytokinesis and to the intercellular bridge connecting postmitotic daughter cells.
GO:0032154 cleavage furrow
IDA
PMID:29079679
Phosphorylation of Pnut in the Early Stages of Drosophila Em...
ACCEPT
Summary: Septin localizes to the cleavage furrow during cytokinesis.
Reason: Septins are recruited to the cleavage furrow of dividing cells; direct immunolocalization in multiple Drosophila cell types. Core location for the cytokinetic role.
Supporting Evidence:
PMID:29079679
All Pnut variants were detected at cell membranes during interphase, and at the cleavage furrow between dividing cells.
GO:0032154 cleavage furrow
IDA
PMID:8181057
The Drosophila peanut gene is required for cytokinesis and e...
ACCEPT
Summary: Septin localizes to the cleavage furrow during cytokinesis.
Reason: Septins are recruited to the cleavage furrow of dividing cells; direct immunolocalization in multiple Drosophila cell types. Core location for the cytokinetic role.
Supporting Evidence:
PMID:8181057
Pnut protein is localized to the cleavage furrow of dividing cells during cytokinesis and to the intercellular bridge connecting postmitotic daughter cells.
GO:0032154 cleavage furrow
IDA
PMID:9813088
Drosophila polo kinase is required for cytokinesis.
ACCEPT
Summary: Septin localizes to the cleavage furrow during cytokinesis.
Reason: Septins are recruited to the cleavage furrow of dividing cells; direct immunolocalization in multiple Drosophila cell types. Core location for the cytokinetic role.
Supporting Evidence:
PMID:9813088
In wild-type cysts, Peanut appears in the cleavage furrow rings at anaphase
GO:0032154 cleavage furrow
IEA
GO_REF:0000044
ACCEPT
Summary: Septin localizes to the cleavage furrow during cytokinesis.
Reason: Septins are recruited to the cleavage furrow of dividing cells; direct immunolocalization in multiple Drosophila cell types. Core location for the cytokinetic role.
Supporting Evidence:
PMID:8181057
Pnut protein is localized to the cleavage furrow of dividing cells during cytokinesis and to the intercellular bridge connecting postmitotic daughter cells.
GO:0042060 wound healing
IMP
PMID:38728140
Two Septin complexes mediate actin dynamics during cell woun...
ACCEPT
Summary: Septins are required for efficient cell wound repair.
Reason: All five septins are required for efficient wound repair of the syncytial embryo; Sep1/Sep2 and Sep4/Sep5 loss give distinct actin-ring phenotypes. Direct IMP evidence; this is single-cell (plasma membrane/cortex) wound repair.
Supporting Evidence:
PMID:38728140
we show that all five Drosophila Septins are required for efficient cell wound repair
PMID:38728140
Consistent with the presence of Pnut in both Septin complexes, Sep2 and Sep5 are no longer recruited in Pnut knockdowns
GO:0042461 photoreceptor cell development
NAS
PMID:8181057
The Drosophila peanut gene is required for cytokinesis and e...
MARK AS OVER ANNOTATED
Summary: Photoreceptor development inferred from a genetic interaction with seven in absentia.
Reason: The only basis is a dominant genetic interaction between pnut and sina noted in PMID:8181057, which the authors interpret as possible pleiotropy. No septin was shown to act in photoreceptor development; for Sep1, Sep2 and Sep4 the NAS row simply extends this pnut observation to paralogs.
Supporting Evidence:
PMID:8181057
pnut displays genetic interactions with seven in absentia, a gene required for neuronal fate determination in the compound eye
GO:0042803 protein homodimerization activity
IDA
PMID:8636235
A purified Drosophila septin complex forms filaments and exh...
KEEP AS NON CORE
Summary: Septin subunits proposed to be present as homodimers in the purified complex.
Reason: The 1996 hydrodynamic data suggested a heterotrimer of homodimers; current models describe a palindromic hexamer assembled through alternating G- and NC-interfaces. Homotypic septin contacts are real but describe complex architecture rather than a distinct function; non-core.
Supporting Evidence:
PMID:8636235
Hydrodynamic and sequence data suggest that the complex is composed of a heterotrimer of homodimers.
GO:0043065 positive regulation of apoptotic process
IDA
PMID:17456438
Drosophila melanogaster Parkin ubiquitinates peanut and sept...
KEEP AS NON CORE
Summary: Septins enhance p53-dependent apoptosis in a cell-based assay.
Reason: Abstract-only reference; the assay reports higher p53-dependent apoptosis in the presence of septins and dopamine, in a Parkin-substrate context. Deferring to the curator, but this is a peripheral, context-specific observation; non-core.
Supporting Evidence:
PMID:17456438
the rate and efficiency of p53-dependent apoptosis were significantly higher
GO:0044837 actomyosin contractile ring organization
IMP
PMID:38728140
Two Septin complexes mediate actin dynamics during cell woun...
ACCEPT
Summary: Septins organise the actomyosin ring during single-cell wound repair.
Reason: In the Drosophila embryo cell-wound model, knockdown or mutation of each septin perturbs actomyosin ring assembly, contraction or disassembly; the two complexes bend actin bundles to different curvatures. Core process for the septin complexes.
Supporting Evidence:
PMID:38728140
we show that all five Drosophila Septins are required for efficient cell wound repair
PMID:38728140
Interestingly, we observe curved F-actin bundles induced by two separate Septin complexes, whereas individual Septins can only bind to and bundle F-actin.
GO:0045171 intercellular bridge
IDA
PMID:8181057
The Drosophila peanut gene is required for cytokinesis and e...
ACCEPT
Summary: Pnut persists at the intercellular bridge after division.
Reason: Immunolocalization shows Pnut at the intercellular bridge connecting postmitotic daughter cells and in germline ring canals.
Supporting Evidence:
PMID:8181057
Pnut protein is localized to the cleavage furrow of dividing cells during cytokinesis and to the intercellular bridge connecting postmitotic daughter cells.
GO:0045572 positive regulation of imaginal disc growth
IMP
PMID:29719260
Yorkie and JNK Control Tumorigenesis in Drosophila Cells wit...
KEEP AS NON CORE
Summary: Loss of Pnut-dependent cytokinesis reduces imaginal disc growth.
Reason: Pnut depletion causes cytokinesis failure, JNK activation and apoptosis that limit disc growth. The growth effect is a downstream consequence of failed cytokinesis rather than a regulatory activity of Pnut; retained as non-core.
Supporting Evidence:
PMID:8181057
in pnut mutants, imaginal tissues fail to proliferate and instead develop clusters of large, multinucleate cells
GO:0051015 actin filament binding
IDA
PMID:38728140
Two Septin complexes mediate actin dynamics during cell woun...
ACCEPT
Summary: Purified septin subunits and complexes bind and bundle actin filaments.
Reason: Each of the five Drosophila septins, purified individually, binds and bundles F-actin in vitro, and the assembled Sep1/Sep2/Pnut and Sep4/Sep5/Pnut complexes additionally bend the bundles into rings. Direct F-actin binding is a core activity linking septins to the actomyosin cytoskeleton.
Supporting Evidence:
PMID:38728140
Strikingly, we find that all five Drosophila Septins can bind to and bundle actin filaments
PMID:38728140
Interestingly, we observe curved F-actin bundles induced by two separate Septin complexes, whereas individual Septins can only bind to and bundle F-actin.
GO:0060090 molecular adaptor activity
IBA
GO_REF:0000033
KEEP AS NON CORE
Summary: Septin filaments act as scaffolds that recruit other proteins.
Reason: IBA from PANTHER node PTN000430171 with donors yeast Cdc3 and Cdc12 (SGD:S000000595, SGD:S000001149), where septin collars scaffold bud-neck proteins. Drosophila septins also act as cortical scaffolds (e.g. with Anillin), but the documented fly activities are actin filament binding and bundling; the generic adaptor term is retained as non-core.
GO:0061640 cytoskeleton-dependent cytokinesis
IBA
GO_REF:0000033
MODIFY
Summary: Septin role in cytoskeleton-dependent cytokinesis inherited from the septin family.
Reason: IBA from PANTHER node PTN000430171 with broad donors (yeast, fission yeast, mouse, worm and the Drosophila septins Pnut, Sep1, Sep2, Sep4 and Sep5; the gene appearing among the donors is expected, not circular). The process is correct but more general than the evidence supports: this gene already carries the more specific child term GO:0000281 mitotic cytokinesis from experimental annotations, so the IBA is better expressed with that term.
Proposed replacements: mitotic cytokinesis
Supporting Evidence:
PMID:8181057
We find that pnut is also required for cytokinesis
GO:0070938 contractile ring
IDA
PMID:10485851
A putative exchange factor for Rho1 GTPase is required for i...
ACCEPT
Summary: Pnut is a component of the contractile ring.
Reason: Pnut is incorporated into the actomyosin contractile ring at the cleavage furrow; its ring incorporation fails when upstream Rho pathway regulators are lost.
Supporting Evidence:
PMID:9813088
In wild-type cysts, Peanut appears in the cleavage furrow rings at anaphase

Core Functions

Pnut is a catalytically active septin GTPase subunit; GTP binding and hydrolysis by the septin G domain drive assembly and dynamics of hetero-oligomeric septin complexes and filaments at the cleavage furrow.

Molecular Function:
GTPase activity
Directly Involved In:
In Complex:
septin complex
Supporting Evidence:
  • PMID:18987337
    the binding of Orc6 to Pnut increases the intrinsic GTPase activity of the Drosophila septin complex
  • PMID:25355953
    We show that Drosophila septin complex functions depend on the intact GTP-binding and/or hydrolysis domains of Pnut, Sep1, and Sep2.
  • PMID:8181057
    We find that pnut is also required for cytokinesis

Pnut binds and bundles actin filaments; as part of a septin hetero-oligomer it bends F-actin bundles into curved rings, organising the actomyosin ring during cytokinesis and single-cell wound repair as the shared subunit of both fly septin complexes.

Supporting Evidence:
  • PMID:38728140
    Strikingly, we find that all five Drosophila Septins can bind to and bundle actin filaments
  • PMID:38728140
    Interestingly, we observe curved F-actin bundles induced by two separate Septin complexes, whereas individual Septins can only bind to and bundle F-actin.
  • PMID:38728140
    we show that all five Drosophila Septins are required for efficient cell wound repair

References

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Deep Research

Falcon

(pnut-deep-research-falcon.md)

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FlyBase

(pnut-deep-research-flybase.md)
FlyBase gene description for pnut (DROME) FlyBase

FlyBase gene description for pnut (DROME)

peanut (pnut) encodes a protein that belongs to the septin family of polymerizing GTPases. Together with the products of Septin1 and Septin2, it forms the septin complex. It participates in cytokinesis and other processes that involve organization of the cell cortex.

πŸ“š Additional Documentation

Notes

(pnut-notes.md)

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πŸ“„ View Raw YAML

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