Current PTHR19375 PAINT annotation snapshot
Falcon deep research report for Saccharomyces cerevisiae SSA1
-
Falcon report synthesizes SSA1/Ssa1 as a highly abundant cytosolic/nuclear Hsp70-family molecular chaperone that uses an ATP-driven NBD/SBD cycle to bind non-native polypeptides and coordinate folding, refolding, disaggregation, trafficking, and degradation, with specificity tuned by J-domain co-chaperones (Sis1/Ydj1) and nucleotide exchange factors (Fes1/Sse1).
-
Recent (2023-2024) work places Ssa1 as a chaperone regulator of the Ste5 MAPK scaffold in the mating pathway, maps an Ssa1/Sis1 binding site on the Sup35 prion domain that governs disaggregation and prion propagation, and resolves how the Ssa1 C-terminal EEVD motif engages the essential J-protein Sis1.
Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Electronic Gene Ontology annotations created by ARBA machine learning models
Combined Automated Annotation using Multiple IEA Methods
The dissociation of ATP from hsp70 of Saccharomyces cerevisiae is stimulated by both Ydj1p and peptide substrates.
Functional interaction of cytosolic hsp70 and a DnaJ-related protein, Ydj1p, in protein translocation in vivo.
-
SSA-family Hsp70 and Ydj1 cooperate in post-translational precursor translocation, with a rapid direct effect on prepro-alpha-factor import.
"The processing of prepro-alpha-factor was inhibited within 2 min of the shift to 37 degrees C, suggesting a direct effect of the hsp70 defect on translocation."
Members of the Hsp70 family of proteins in the cell wall of Saccharomyces cerevisiae.
-
Ssa1/Ssa2 Hsp70 products were detected in the yeast cell wall by complementary surface-localization methods.
"A cell wall location was further confirmed by indirect immunofluorescence with intact cells and biotinylation of extracellular Hsp70."
The refolding activity of the yeast heat shock proteins Ssa1 and Ssa2 defines their role in protein translocation.
-
Ssa1/2 depletion strongly impaired refolding of chemically denatured luciferase in yeast cytosol.
"Depletion of Ssa1/2p had no effect on the ability of the yeast lysate to synthesize enzymatically active luciferase, but had a dramatic effect on the ability of the lysate to refold chemically denatured luciferase."
-
Ssa1/2 depletion did not reduce co- or post-translational translocation in the cell-free assay.
"Depletion of Ssa1/2p had no effect on the efficiency of translocation in this in vitro assay."
Molecular mechanism governing heme signaling in yeast: a higher-order complex mediates heme regulation of the transcriptional activator HAP1.
Hsp104, Hsp70, and Hsp40: a novel chaperone system that rescues previously aggregated proteins.
-
Hsp104 cooperates with Hsp70 and Hsp40 to reactivate previously aggregated proteins.
"However, in concert with Hsp40 and Hsp70, Hsp104 can reactivate proteins that have been denatured and allowed to aggregate, substrates refractory to the action of other chaperones."
Folding in vivo of a newly translated yeast cytosolic enzyme is mediated by the SSA class of cytosolic yeast Hsp70 proteins.
-
SSA-family cytosolic Hsp70s assist folding of newly translated cytosolic enzymes in vivo.
"These findings indicate that, in vivo, the Hsp70 system assists in folding at least some newly translated cytosolic enzymes, most likely functioning in a posttranslational manner."
Cns1 is an essential protein associated with the hsp90 chaperone complex in Saccharomyces cerevisiae that can restore cyclophilin 40-dependent functions in cpr7Delta cells.
A nuclear export signal prevents Saccharomyces cerevisiae Hsp70 Ssb1p from stimulating nuclear localization signal-directed nuclear transport.
Cytosolic Hsp70s are involved in the transport of aminopeptidase 1 from the cytoplasm into the vacuole.
-
Ssa1/2 participate in Ape1 transport and localize prominently to the vacuolar membrane.
"Ssa1/2p was prominently localized to the vacuolar membrane, consistent with the role we propose for Ssa proteins in the fusion of transport vesicles with the vacuolar membrane."
The yeast hsp70 homologue Ssa is required for translation and interacts with Sis1 and Pab1 on translating ribosomes.
Subcellular localization of the yeast proteome.
The ctf13-30/CTF13 genomic haploinsufficiency modifier screen identifies the yeast chromatin remodeling complex RSC, which is required for the establishment of sister chromatid cohesion.
A novel mode of chaperone action: heme activation of Hap1 by enhanced association of Hsp90 with the repressed Hsp70-Hap1 complex.
Navigating the chaperone network: an integrative map of physical and genetic interactions mediated by the hsp90 chaperone.
An integrated mass spectrometry-based proteomic approach: quantitative analysis of tandem affinity-purified in vivo cross-linked protein complexes (QTAX) to decipher the 26 S proteasome-interacting network.
Proteome survey reveals modularity of the yeast cell machinery.
The plasma membrane proteome of Saccharomyces cerevisiae and its response to the antifungal calcofluor.
-
The study identified proteins from a stripped yeast plasma-membrane fraction; the cached abstract does not independently verify the Ssa1-specific identification.
"Proteins from a stripped plasma membrane fraction were solubilized with the neutral and non-denaturing detergent, the n-dodecyl beta-D-maltoside."
Chaperone network in the yeast cytosol: Hsp110 is revealed as an Hsp70 nucleotide exchange factor.
SGT2 and MDY2 interact with molecular chaperone YDJ1 in Saccharomyces cerevisiae.
Structure-templated predictions of novel protein interactions from sequence information.
Structural basis for the cooperation of Hsp70 and Hsp110 chaperones in protein folding.
Prion-impairing mutations in Hsp70 chaperone Ssa1: effects on ATPase and chaperone activities.
-
Biochemical characterization of SSA1 ATPase and refolding activities
-
Mutations alter ATPase, substrate binding, and refolding differently
High-quality binary protein interaction map of the yeast interactome network.
An atlas of chaperone-protein interactions in Saccharomyces cerevisiae: implications to protein folding pathways in the cell.
Ubr1 and Ubr2 function in a quality control pathway for degradation of unfolded cytosolic proteins.
Combinatorial depletion analysis to assemble the network architecture of the SAGA and ADA chromatin remodeling complexes.
Control of the function of the transcription and repair factor TFIIH by the action of the cochaperone Ydj1.
CDK-dependent Hsp70 Phosphorylation controls G1 cyclin abundance and cell-cycle progression.
Clathrin coat disassembly by the yeast Hsc70/Ssa1p and auxilin/Swa2p proteins observed by single-particle burst analysis spectroscopy.
Rrp5 binding at multiple sites coordinates pre-rRNA processing and assembly.
Coordination of translational control and protein homeostasis during severe heat stress.
Cytosolic Hsp70 and co-chaperones constitute a novel system for tRNA import into the nucleus.
One library to make them all: streamlining the creation of yeast libraries via a SWAp-Tag strategy.
The requirements of yeast Hsp70 of SSA family for the ubiquitin-dependent degradation of short-lived and abnormal proteins.
A protein quality control pathway at the mitochondrial outer membrane.
RNA-dependent interactome allows network-based assignment of RNA-binding protein function.
The social and structural architecture of the yeast protein interactome.
OpenScientist hypothesis review of the SSA1 plasma-membrane annotations
-
The Ssa1 plasma-membrane evidence is a bulk fractionation observation rather than demonstration of a stable functional pool; retaining it as non-core is conservative.
"Because the annotation reflects bulk co-purification rather than a demonstrated functional site, treating plasma membrane as **non-core is the correct handling of the evidence weight**"