biostudies-literatureKang YHSwiss National Science Foundation1145-54https://www.ebi.ac.uk/biostudies/studies/S-EPMC4967951biostudies-literatureUnknown17(8)Receptor kinases convey diverse environmental and developmental inputs by sensing extracellular ligands. In plants, one group of receptor-like kinases (RLKs) is characterized by extracellular leucine-rich repeat (LRR) domains, which interact with various ligands that include the plant hormone brassinosteroid and peptides of the CLAVATA3/EMBRYO SURROUNDING REGION (CLE) type. For instance, the CLE45 peptide requires the LRR-RLK BARELY ANY MERISTEM 3 (BAM3) to prevent protophloem formation in Arabidopsis root meristems. Here, we show that other proposed CLE45 receptors, the two redundantly acting LRR-RLKs STERILITY-REGULATING KINASE MEMBER 1 (SKM1) and SKM2 (which perceive CLE45 in the context of pollen tube elongation), cannot substitute for BAM3 in the root. Moreover, we identify MEMBRANE-AEMBO reportsArabidopsis MAKR5 is a positive effector of BAM3-dependent CLE45 signaling.PMC4967951147088310030B_147088Hardtke CSKang YHfalseArabidopsis MAKR5 is a positive effector of BAM3-dependent CLE45 signaling.Receptor kinases convey diverse environmental and developmental inputs by sensing extracellular ligands. In plants, one group of receptor-like kinases (RLKs) is characterized by extracellular leucine-rich repeat (LRR) domains, which interact with various ligands that include the plant hormone brassinosteroid and peptides of the CLAVATA3/EMBRYO SURROUNDING REGION (CLE) type. For instance, the CLE45 peptide requires the LRR-RLK BARELY ANY MERISTEM 3 (BAM3) to prevent protophloem formation in Arabidopsis root meristems. Here, we show that other proposed CLE45 receptors, the two redundantly acting LRR-RLKs STERILITY-REGULATING KINASE MEMBER 1 (SKM1) and SKM2 (which perceive CLE45 in the context of pollen tube elongation), cannot substitute for BAM3 in the root. Moreover, we identify MEMBRANE-A2016-01-01T00:00:00Z2016 Aug2026-05-05T15:42:14.602Z2019-03-27T02:19:34ZS-EPMC49679512735441610.15252/embr.201642450