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The NLR protein SUMM 2 senses the disruption of an immune signaling MAP kinase cascade via CRCK 3
Author(s) -
Zhang Zhibin,
Liu Yanan,
Huang Hao,
Gao Minghui,
Wu Di,
Kong Qing,
Zhang Yuelin
Publication year - 2017
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.201642704
Subject(s) - beijing , library science , chinese academy of sciences , china , columbia university , history , archaeology , media studies , sociology , computer science
MAP kinase signaling is an integral part of plant immunity. Disruption of the MEKK 1‐ MKK 1/2‐ MPK 4 kinase cascade results in constitutive immune responses mediated by the NLR protein SUMM 2, but the molecular mechanism is so far poorly characterized. Here, we report that SUMM 2 monitors a substrate protein of MPK 4, CALMODULIN ‐ BINDING RECEPTOR ‐ LIKE CYTOPLASMIC KINASE 3 ( CRCK 3). Similar to SUMM 2, CRCK 3 was isolated from a suppressor screen of mkk1 mkk2 and is required for the autoimmunity phenotypes in mekk1 , mkk1 mkk2, and mpk4 mutants. In wild‐type plants, CRCK 3 is mostly phosphorylated. MPK 4 interacts with CRCK 3 and can phosphorylate CRCK 3 in vitro . In mpk4 mutant plants, phosphorylation of CRCK 3 is substantially reduced, suggesting that MPK 4 phosphorylates CRCK 3 in vivo . Further, CRCK 3 associates with SUMM 2 in planta , suggesting SUMM 2 senses the disruption of the MEKK 1‐ MKK 1/2‐ MPK 4 kinase cascade through CRCK 3. Our study suggests that a MAP kinase substrate is used as a guardee or decoy for monitoring the integrity of MAP kinase signaling.