Serine/Threonine-Protein Kinase BIK1 (BIK1) Arabidopsis Thaliana Recombinant Protein

Encodes a plasma membrane-localized ser/thr protein kinase that is a crucial component of host response signaling required to activate the resistance responses to Botrytis and A. brassicicola infection. It is likely a negative regulator of salicylic acid accumulation and basal defense against virulent bacterial pathogens.

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).