CEBIP (rice, Q8H8C7) curation notes

2026-10-02 — initial review

Sources: UniProt record, falcon deep research (CEBIP-deep-research-falcon.md), cached publications.
Only PMID:21070404 has full text cached; the others are abstract-only.

Identity and architecture

• 356-aa precursor with a 28-aa signal peptide; mature protein is heavily N-glycosylated PMID:16829581.
• C-terminal hydrophobic segment PMID:16829581. UniProt annotates a single-pass TM helix (336-356); GPI anchoring is proposed for LysM-RLPs in other species but has not been shown for rice CEBiP (deep research flags this too).
• Crystal structure: PMID:27238968

Molecular function: chitin binding / PRR

• Purified from plasma membrane by affinity PMID:16829581.
• Specificity PMID:24395781
• Sandwich dimer PMID:24395781
• Major binding site in vivo PMID:24173912.

Receptor complex with OsCERK1

• PMID:21070404
• Pre-formed CEBiP homo-oligomers; chitin-induced hetero-complex PMID:21070404.
• Downstream: OsCERK1 phosphorylates OsRacGEF1 PMID:23601108 -> kinase steps belong to OsCERK1, not CEBiP.

Biological role

• RNAi: PMID:16829581.
• Knockout: chitin-specific PMID:24173912; resistance phenotype only with weakly virulent blast strain.
• Slp1: PMID:22267486; CEBiP silencing lets M. oryzae cause disease without Slp1.
• Arabidopsis orthologue LYM2/AtCEBiP binds chitin but does not signal PMID:22891159 -> do not transfer receptor/process terms between rice and Arabidopsis by orthology.
• Symbiosis: per deep research (Zhang et al. 2021 PNAS, not cached), CEBiP competes with OsMYR1 for OsCERK1; cebip mutants show increased early AM colonization. Indirect; not annotated.

Decisions

• protein binding (IPI, OsCERK1) -> MODIFY to GO:0038187 pattern recognition receptor activity.
• plasma membrane (IEA) -> ACCEPT. chitin binding (IBA) -> ACCEPT.
• NEW: GO:0032491 detection of molecule of fungal origin; GO:0002752 cell surface PRR signaling pathway (CEBiP performs the ligand-binding initiation step; comparators OsCERK1, AtCERK1, AtLYK5).
• Not added: defense response to fungus / innate immune response (outcome-level; necessity evidence, and blast phenotype is weak in knockout).
• UniProt cites PMID:24964058 for CEBiP-LYP4/LYP6 interaction, but the abstract reports OsCERK1-LYP4/LYP6; full text not available, left UNVERIFIED.