Plant cell surface molecular cypher: Receptor-like proteins and their roles in immunity and development

•Receptor-like proteins (RLPs) are transmembrane proteins with diverse functions in both plant development and immunity.•Due to their lack of an intracellular kinase domain, RLPs often complex with receptor-like kinases (RLKs) for ligand perception and/or signal relay.•RLPs may regulate RLK protein stability or function as a specificity switch for ligand-receptor recognition.•Some RLPs and RLKs are physically clustered, and sometimes they correlate in expression and physical proximity—although the biological function is not clear.•LRR-RLP protein sequences suggest RLP diversity is likely due to an expansion and neofunctionalization from different RLPs subsets.