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.