## HSPB7
- **UniProt:** Q9UBY9 · **batch:** proteostasis-batch-2026-06-07b · **review status:** COMPLETE
- **PN placement:** one row — `Cytonuclear proteostasis|Chaperone|small HSP system|small HSP` (type) ; **PN-node mapping:** sHSP type → mapped/ok_for_propagation_to_go GO:0044183 protein folding chaperone (new_to_goa); group/class/branch no_mapping.
- **Consistency:** Notes ↔ review converge tightly — HSPB7/cvHsp is a NON-canonical sHSP that does NOT refold denatured substrate (PMID:19464326 "HSPB7 did not support refolding"); it sequesters aggregation-prone clients (polyQ, filamin) and binds alpha-filamin (PMID:10593960). Cardiac-enriched, SC35-speckle resident. This directly contradicts the PN GO:0044183 (foldase) projection.
- **PN story / NEW pressure:** GOA has no folding-chaperone MF for HSPB7 (has GO:0031005 filamin binding, GO:0006986 BP). PN projects GO:0044183 protein folding chaperone (verified real, but a FOLDASE per OLS — "binds an unfolded protein to fold it"). HSPB7 is explicitly a non-foldase sequestrase, so GO:0044183 is the most over-reaching projection of the six sHSPs here. The review's genuine MFs are GO:0031005 filamin binding (ACCEPT) and GO:0051082 unfolded protein binding (holdase/sequestrase, core). The defensible MF gap, if any, is GO:0140309 unfolded protein holdase activity / GO:0051082, NOT GO:0044183.
- **Mapping strategy:** This gene is the exemplar where the sHSP-family GO:0044183 mapping is wrong: HSPB7 is a poor classical holdase and an outright non-foldase. GO:0044183 is broader-and-wrong (foldase activity HSPB7 lacks). Either re-scope the sHSP "small HSP" type away from a foldase term, or flag HSPB7 as an exception on Q9UBY9.
- **Evidence alignment:** PN row carries no reference titles; review PMIDs (19464326, 10593960, 14594798, plus interactome set) cover the non-refolding phenotype, filamin binding, and sHSP hetero-oligomers — no overlap to diverge, but the key review finding (no refolding) refutes the PN projection.
- **Verdict:** sHSP membership correct but the GO:0044183 foldase projection is contradicted by direct evidence; over-reaches. **Recommended edits:** [MAP] do not project GO:0044183 protein folding chaperone onto Q9UBY9 (HSPB7 demonstrably does not refold; PMID:19464326); if a shared sHSP MF is desired use GO:0140309 unfolded protein holdase activity / GO:0051082 unfolded protein binding, and mark HSPB7 a non-canonical exception.