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Arabidopsis MAKR 5 is a positive effector of BAM 3‐dependent CLE 45 signaling
Author(s) -
Kang Yeon Hee,
Hardtke Christian S
Publication year - 2016
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201642450
Subject(s) - arabidopsis , brassinosteroid , biology , microbiology and biotechnology , kinase , signal transduction , meristem , arabidopsis thaliana , regulator , effector , context (archaeology) , genetics , gene , mutant , paleontology
Receptor kinases convey diverse environmental and developmental inputs by sensing extracellular ligands. In plants, one group of receptor‐like kinases ( RLK s) is characterized by extracellular leucine‐rich repeat ( LRR ) domains, which interact with various ligands that include the plant hormone brassinosteroid and peptides of the CLAVATA 3/ EMBRYO SURROUNDING REGION ( CLE ) type. For instance, the CLE 45 peptide requires the LRR ‐ RLK BARELY ANY MERISTEM 3 ( BAM 3) to prevent protophloem formation in Arabidopsis root meristems. Here, we show that other proposed CLE 45 receptors, the two redundantly acting LRR ‐ RLK s STERILITY ‐ REGULATING KINASE MEMBER 1 ( SKM 1) and SKM 2 (which perceive CLE 45 in the context of pollen tube elongation), cannot substitute for BAM 3 in the root. Moreover, we identify MEMBRANE ‐ ASSOCIATED KINASE REGULATOR 5 ( MAKR 5) as a post‐transcriptionally regulated amplifier of the CLE 45 signal that acts downstream of BAM 3. MAKR 5 belongs to a small protein family whose prototypical member, BRI 1 KINASE INHIBITOR 1, is an essentially negative regulator of brassinosteroid signaling. By contrast, MAKR 5 is a positive effector of CLE 45 signaling, revealing an unexpected diversity in the conceptual roles of MAKR genes in different signaling pathways.