BKI1 (At5g42750, UniProtKB:Q9FMZ0) curation notes

Session 2026-10-05/06 (brassinosteroid_signaling module curation).

• Identity checked: BKI1_ARATH, Q9FMZ0, At5g42750.
• Falcon deep research attempted; provider returned HTTP 402 (no report produced).
• BKI1 is a BRI1-interacting negative regulator PMID:16857903
• Mechanism: limits BRI1-BAK1 association PMID:16857903
• Release by Tyr phosphorylation in [KR][KR] membrane motif PMID:21289069
• Positive role of released BKI1 via 14-3-3 PMID:22075146
• GO:0010423 (negative regulation of BR biosynthesis) IMP + IBA: sign looks inconsistent with BKI1 being an inhibitor of signalling (signalling represses biosynthesis); left UNDECIDED since PMID:16857903 is abstract-only.
• Added NEW GO:1900458 negative regulation of BR mediated signaling pathway (BKI1 performs the inhibitory step itself).
• Nuclear ISM prediction removed (no evidence; polybasic motif likely mis-read as NLS).

Follow-up (resolving UNDECIDED rows)

• Europe PMC: PMID:16857903 has no PMC/open-access full text.
• Web search: Wang et al. 2011 Dev Cell (PMID:22075146) reportedly shows that BKI1-YFP overexpression increases CPD and DWF4 expression. If so, the sign of GO:0010423 (negative regulation of BR biosynthesis) is doubtful. Not verified from cached text.
• Decision: the IMP is kept as KEEP_AS_NON_CORE, deferring to the curator with the sign caveat. The IBA (node seeded only by BKI1's own IMP) is set to MARK_AS_OVER_ANNOTATED with a propagation_review (SOURCE_WEAK_OR_INFERRED; REGULATORY_SIGN_INVERSION, ROLE_CONFLATION).