5tos
Botrytis-induced kinase 1 (BIK1) from Arabidopsis thaliana
Structural highlights
FunctionBIK1_ARATH Plays a central role in immune responses (PubMed:20413097). Required to activate the resistance responses to necrotrophic pathogens (PubMed:16339855). Phosphorylates FLS2 and BAK1 (PubMed:20404519, PubMed:24104392). Involved in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) signaling and defense responses downstream of FLS2. Acts additively with PBL1 in PTI defenses (PubMed:20413097). Acts as positive regulator of the PAMP flg22-induced increase of cytosolic calcium. Binds directly and phosphorylates the NADPH oxidase RBOHD at specific sites in a calcium-independent manner to enhance reactive oxygen species (ROS) generation upon flg22 perception. ROS production in response to flg22 controls stomatal movement and restriction of bacterial entry into leaf tissues (PubMed:24629339). Seems not required for flg22-induced MAPK activation (Probable). Required for Pep1-induced defenses. Pep1 is an endogenous elicitor that potentiates PAMP-inducible plant responses. In association with PEPR1, acts downstream of the canonical ethylene signaling cascade to regulate ethylene responses (PubMed:23431184). Involved in ethylene signaling. Destabilizes EIN3, the key transcription activator in ethylene signaling, and represses EIN3-dependent transcription (PubMed:26021844). Acts as a negative regulator in brassinosteroid (BR) signaling. Functions in BR signaling by direct interaction with the BR receptor BRI1 cytosolic kinase domain (PubMed:23818580).[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedPlants employ cell-surface pattern recognition receptors (PRRs) to detect pathogens. Although phytohormones produced during PRR signaling play an essential role in innate immunity, a direct link between PRR activation and hormone regulation is unknown. EFR is a PRR that recognizes bacterial EF-Tu and activates immune signaling. Here we report that EFR regulates the phytohormone jasmonic acid (JA) through direct phosphorylation of a receptor-like cytoplasmic kinase, BIK1. The BIK1 structure revealed that the EFR-phosphorylated sites reside on a uniquely extended loop away from the BIK1 kinase core domain. Phosphomimetic mutations of these sites resulted in increased phytohormones and enhanced resistance to bacterial infections. In addition to its documented plasma membrane localization, BIK1 also localizes to the nucleus and interacts directly with WRKY transcription factors involved in the JA and salicylic acid (SA) regulation. These findings demonstrate the mechanistic basis of signal transduction from PRR to phytohormones, mediated through a PRR-BIK1-WRKY axis. The Receptor-like Cytoplasmic Kinase BIK1 Localizes to the Nucleus and Regulates Defense Hormone Expression during Plant Innate Immunity.,Lal NK, Nagalakshmi U, Hurlburt NK, Flores R, Bak A, Sone P, Ma X, Song G, Walley J, Shan L, He P, Casteel C, Fisher AJ, Dinesh-Kumar SP Cell Host Microbe. 2018 Apr 11;23(4):485-497.e5. doi: 10.1016/j.chom.2018.03.010. PMID:29649442[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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