Review. Alternative modes of RLK function: Insights into cleavage-driven plant signaling

Receptor-like kinases (RLKs) constitute a large family of membrane-bound proteins in plants. The Arabidopsis genome encodes over 600 RLKs, while the rice genome contains more than 1,000. RLKs are best known for their role in perceiving environmental stimuli and triggering downstream signaling pathways that promote stress resilience, primarily through protein–protein interactions and phosphorylation cascades. Interestingly, some truncated forms of RLKs appear to function independently of ligand binding, suggesting alternative mechanisms of action. Yu and colleagues review accumulating evidence supporting proteolytic cleavage as a regulatory mechanism for RLK function. They describe two main cleavage modes: (1) ectodomain shedding, where the extracellular domain is released and acts as a signaling molecule to facilitate plant–microbe symbiosis; and (2) intracellular domain shedding, in which the cytoplasmic kinase domain is released and translocates into the nucleus to activate transcriptional programs. Although research in this area remains limited and identifying the responsible proteases is technically challenging, this review highlights an emerging direction in understanding the dynamic and multifaceted roles of RLKs in plant signaling. (Summary by Ching Chan @ntnuchanlab) New Phytol. 10.1111/nph.70174