SSA3 review notes
Description cleanup note
The YAML description field was revised to keep it as a standalone biological summary. Project-specific curation framing moved here instead.
- Moved out of the YAML description: wording was adjusted from
cytosol/nucleus proteostasis network to avoid confusion with project-specific Proteostasis Network terminology.
2026-08-22 re-review
- Identity was rechecked as Saccharomyces cerevisiae SSA3/YBL075C, UniProt
P09435: the stress-inducible cytosolic Ssa-family Hsp70 paralog. SSA3 is
normally expressed at very low levels but can provide essential Ssa function
when expressed constitutively. PMID:3302682
- The core function is consolidated as ATP-dependent protein folding chaperone
activity (GO:0140662) in cytosolic folding/refolding. The broader
GO:0044183 IBA is modified to that mechanistically precise child term, and
generic nucleotide binding is marked over-annotated because ATP binding and
ATP hydrolysis are already represented. SSA-family Hsp70 is experimentally
required for folding newly translated cytosolic proteins. PMID:9789005
- The two GO:0006616 annotations are modified rather than simply retained as
non-core. Becker et al. tested precursor import into the ER and mitochondria,
with the strongest rapid direct effect on ER prepro-alpha-factor import. The
replacement therefore uses the ER-scoped post-translational sibling
GO:0031204, not the existing SRP-dependent cotranslational label; the separate
mitochondrial phenotype is not encoded by that replacement. PMID:8754838
- The plasma-membrane IBA is removed as a stale PAINT transfer. The pinned 2025
GOA row points to PTN002500132, but the current local PTHR19375 PAINT snapshot
carries nucleus and cytosol at that node and no longer carries GO:0005886.
This is a current-node comparison, not an inference from donor count. UniProt
and the SSA3-focused literature consistently identify Ssa3 as cytosolic; no
target-specific plasma-membrane evidence was found. A
targeted OpenScientist hypothesis run independently preferred REMOVE because
it found no SSA3-specific experimental support. Its live QuickGO claims that
the P09435 IBA had been retired and that Ssa4 lacked the same IBA conflict with
the repository's pinned GOA snapshots, so those claims are explicitly marked
disputed and are not used in the decision. [file:yeast/SSA3/SSA3-hypotheses/existing-go-0005886-keep-as-non-core/openscientist.md
"The plasma-membrane assignment is a phylogenetic (IBA) inference only"]
- The PMID:10745074 cached abstract is not treated as a direct SSA3 localization
experiment: it describes cytoplasmic Ssa-family Hsp70s but reports the detailed
transport/localization results for Ssa1/2. The cytosol annotation remains
accepted because that location is independently established and the curator
had access to more evidence than the cached abstract.
- The UNFOLDED_PROTEIN_BINDING project row now uses GO:0140662 for SSA3, aligning
the project decision with the review's ATP-dependent Hsp70 mechanism.
2026-08-27 row-completeness follow-up
- The review was promoted from
DRAFT to COMPLETE after restoring one review
record for every one of the 55 pinned GOA rows. Repeated IPI and IGI rows are retained
separately by reference and WITH/FROM partner rather than collapsed.
- Generic nucleotide binding is now
MODIFY to the existing specific ATP-binding
term GO:0005524, matching the treatment of the same parent term in SSA4.
2026-09-29 IBA follow-up
- Rechecked all eight GO_REF:0000033 IBA rows against
interpro/panther/PTHR19375/PTHR19375-paint.tsv. The accepted nucleus,
cytoplasm, cytosol, ATPase, heat-shock-protein-binding, protein-folding
chaperone, and protein-refolding transfers all still trace to current PAINT
rows; the pinned plasma-membrane IBA remains stale because current
PTN002500132 carries only GO:0005634 nucleus and GO:0005829 cytosol.
- Recorded the 2026 fungal PTN001065099
GO:0042026 protein refolding NOT/IRD
and retained the SSA3 transfer because the pinned row still descends from the
PTN000452648 refolding IBD and has no GO:0006457 protein folding
replacement IBA.
- Added missing
propagation_review.source_entities blocks for the accepted
IBA rows and expanded the PTN-only chaperone IBA with representative current
donors from PTN000452648.
- Searched PubMed for exact
SSA3/Ssa3/YBL075C mentions in 2025-2026 and
found no new exact-match papers that change the Ssa3 curation.
- Converted the legacy bare
GO:0005515 protein binding rows from generic
high-throughput interaction datasets to REMOVE; the two Hsp70-paralog
interaction rows remain MODIFY to GO:0030544 Hsp70 protein binding.
2026-10-01 current-GOA refresh follow-up
- Forced a current
fetch-gene refresh because live GOA for SSA3 has moved from
55 historical rows to 19 rows. The review now keeps all historical source
assertions and marks rows that no longer exactly match live GOA as
retired: true rather than losing the earlier curation.
- Reviewed all newly exact current rows: the refreshed PTN002321897
GO:0005737 cytoplasm and PTN000452648 GO:0016887 ATP hydrolysis activity
IBAs are accepted as supported inherited Ssa/Hsp70 assertions, the refreshed
PTN000452648 GO:0044183 protein folding chaperone IBA remains a sound
transfer but is narrowed to GO:0140662 ATP-dependent protein folding
chaperone, InterPro2GO GO_REF:0000002 now provides the ATP-binding and
ATP-hydrolysis IEAs, and the new ARBA GO:0030163 protein catabolic process
row is kept as non-core because degradation is a contextual branch of Ssa
client handling.
- The 2026 PAINT rows still use SSA3 itself as a descendant evidence source for
cytoplasm and ATP hydrolysis. This is correct for an inherited IBA grounded in
target-family experimental evidence, not circular support.
- Searched PubMed for exact
SSA3/Ssa3/YBL075C mentions in 2025-2026.
The only exact hit was PMID:41314856, a Saccharomyces boulardii
gastric/intestinal stress proteomics study that mentions APJ1 and SSA3 as
condition-specific chaperone hubs in the abstract; it did not change the
S. cerevisiae S288C GO review.