A Regulatory Module Controlling Homeostasis of a Plant Immune Kinase

Wang, Jinlong, Grubb, Lauren, Wang, Jiayu, Liang, Xiangxiu, Li, Lin, Gao, Chulei, Ma, Miaomiao, Feng, Feng, Li, Meng, Li, Lei, Zhang, Xiaojuan, Yu, Feifei, Xie, Qi, Chen, She, Zipfel, Cyril, Monaghan, Jacqueline and Zhou, Jian-Min (2018) A Regulatory Module Controlling Homeostasis of a Plant Immune Kinase. Molecular Cell, 69 (3). 493-504.e6. ISSN 1097-2765

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Abstract

Plant pattern recognition receptors (PRRs) perceive microbial and endogenous molecular patterns to activate immune signaling. The cytoplasmic kinase BIK1 acts downstream of multiple PRRs as a rate-limiting component, whose phosphorylation and accumulation are central to immune signal propagation. Previous work identified the calcium-dependent protein kinase CPK28 and heterotrimeric G proteins as negative and positive regulators of BIK1 accumulation, respectively. However, mechanisms underlying this regulation remain unknown. Here we show that the plant U-box proteins PUB25 and PUB26 are homologous E3 ligases that mark BIK1 for degradation to negatively regulate immunity. We demonstrate that the heterotrimeric G proteins inhibit PUB25/26 activity to stabilize BIK1, whereas CPK28 specifically phosphorylates conserved residues in PUB25/26 to enhance their activity and promote BIK1 degradation. Interestingly, PUB25/26 specifically target non-activated BIK1, suggesting that activated BIK1 is maintained for immune signaling. Our findings reveal a multi-protein regulatory module that enables robust yet tightly regulated immune responses.

Item Type: Article
Uncontrolled Keywords: innate immunity,ubiquitination,phosphorylation,heterotrimeric g proteins,calcium-dependent protein kinases,arabidopsis,pseudomonas syringae,botrytis cinerea
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Pure Connector
Date Deposited: 20 Dec 2017 06:06
Last Modified: 22 Jun 2020 23:53
URI: https://ueaeprints.uea.ac.uk/id/eprint/65773
DOI: 10.1016/j.molcel.2017.12.026

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