## SRPRB
- **UniProt:** Q9Y5M8 · **batch:** proteostasis-batch-2026-06-11 · **review status:** COMPLETE
- **PN placement:** `ER proteostasis|Protein transport|SRP receptor subunit` ; **PN-node mapping:** group=mapped scope=ok_for_propagation_to_go→GO:0006614 (SRP-dependent cotranslational protein targeting to membrane); class `Protein transport`=mapped→GO:0015031; branch=no_mapping.
- **Consistency:** Largely consistent. Deep research, review YAML, and PN annotation agree SRPRB is the membrane-anchored beta subunit of the SRP receptor (a Ras/Arf/Sar1-family GTPase) that docks the SRP-RNC complex at the ER. PN "SRP receptor subunit"→GO:0006614 matches the review's core BP (GO:0045047 protein targeting to ER + GO:0006617 signal-sequence-recognition child, ACCEPT; goa_status here is entailed_by_goa_closure, correctly reflecting that SRPRB's GOA carries GO:0045047/0006617 rather than GO:0006614 directly). One internal review flag: GO:0005881 cytoplasmic microtubule (IDA, PMID:23264731) — re-examined below.
- **PN story / NEW pressure:** PN asserts only the canonical SR docking role in cotranslational targeting, already captured (GO:0045047, GO:0006617, GO:0005785 SR complex, GO:0005525 GTP binding, GO:0005789 ER membrane). A genuinely novel SRbeta function — coordinating cotranslational N-glycosylation via OST engagement (PMID:36921042) — is in the review references but is not the PN story; nearest GO term GO:0180058 (verified real, OST-centric) is not a clean fit. Conclusion: **already captured** for the PN node (no NEW pressure on the mapping).
- **Mapping strategy:** No change needed. GO:0006614 closure-entailed projection is consistent with the review's accepted GO:0045047/0006617 (both descend the same ER-targeting branch); not broader than the review in a problematic way. Class-level GO:0015031 is a broad class target, not asserted of SRPRB.
- **Evidence alignment:** PN dossier lists no reference titles; alignment via projected-term provenance. Review's core support (PMID:16439358 SR-beta/SRalpha Longin structure; PMID:29567807 prehandover cryo-EM; PMID:34020957 SR compaction/GTPase; PMID:37643813 SRPRB KO stabilizes SRalpha) all encode SR docking biology. **MTR120 re-examination:** the cached full text of PMID:23264731 (now available) is entirely about MTR120/KIAA1383, a 120 kDa MT-associated protein found in an ORFeome localization screen; SRPRB (Q9Y5M8, 271 aa ER GTPase) is never mentioned or assayed. The GO:0005881 cytoplasmic-microtubule IDA on SRPRB is a definitive mis-attribution (wrong protein), not merely unverifiable — the review's UNDECIDED was conservative only because full text was unavailable; it now is.
- **Verdict:** Consistent for the PN node; PN already captured. One warranted edit: with full text confirming PMID:23264731 does not assay SRPRB, the cytoplasmic-microtubule annotation should move from UNDECIDED to MARK_AS_OVER_ANNOTATED (wrong-gene citation; correctness → WRONG_IDENTIFIER).