CLV2 (CLAVATA2, AtRLP10, At1g65380; UniProt O80809) curation notes

Identity

• UniProt O80809, receptor-like protein with extracellular LRRs, a single TM helix, and a short cytoplasmic tail with no kinase domain PMID:10521522.

Key findings

• Genetics: clv2 enlarges shoot and floral meristems, acting in the CLV1/CLV3 pathway for meristems but separately for organ development PMID:9729492.
• CLV2/CRN acts in parallel with CLV1 PMID:18381924.
• CLV2 and CRN need each other for ER export PMID:19933383.
• Ligand binding is disputed:
• Radioligand binding gives a Kd of about 32 nM for CLV2 PMID:20626648.
• Photoaffinity labelling found no binding [PMID:25754504 "We showed that CLV2 and RPK2 exhibited no direct binding to the CLV3 peptide."; "the CLV2/CRN complex and RPK2 are not involved in direct ligand interactions but may act as co-receptors."].
• The deep research (falcon) also notes that direct binding by the physiological heteromer is not established.
• Decision: core MF is coreceptor activity (GO:0015026). The IMP GO:0001653 is MODIFIED to it, and the CLE IPI rows are MODIFIED to peptide hormone binding (GO:0017046), matching the CLV1 review's use of that term. The MODIFY rests on the radioligand data the curator used; the photoaffinity refutation is stated in each row's summary rather than cited as support, and GO:0017046 is not used as a core function.
• Root: CLV2 is required for the response to CLE peptides that consume the root meristem PMID:16055633. CLV2/CRN is needed to sense root-active CLEs, with the main action in the protophloem PMID:28607033. CLE14 acts through CLV2 under low phosphate PMID:28586647.
• CIK co-receptors PMID:29581511.
• Nematode CLE mimics PMID:21265896.

Decisions summary

• Accepted: plasma membrane, regulation of meristem growth, meristem development, and IBA signaling receptor activity.
• Kept as non-core: ER membrane (transit compartment), root, phloem and organ phenotypes.
• Modified:
• Protein binding with CRN to signaling receptor binding.
• Protein binding with CLE peptides to peptide hormone binding.
• Signal transduction to cell surface receptor signaling pathway.

PR #4384 review follow-up (2026-10-06)

• Removed PMID:25754504 ("no direct binding") from supported_by of the CLE-peptide MODIFY rows: it refutes rather than supports the action; the dispute stays in each row's summary. Reworded reason so it justifies the MODIFY instead of claiming non-core.
• Trimmed the GO:0015026 reason: coreceptor activity entails combining with the messenger, so it is not fully neutral on the binding dispute.