Protein: Serine/threonine-protein kinase BIK1 (EC 2.7.11.1) (Protein BOTRYTIS-INDUCED KINASE 1) (O48814)
Organism: Arabidopsis thaliana (Mouse-ear cress)
Function: Plays a central role in immune responses. Required to activate the resistance responses to necrotrophic pathogens, including the regulation of defense hormone expression (e.g. jasmonic acid (JA) and salicylic acid (SA)). Phosphorylates FLS2 and BAK1. Involved in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) signaling, including calcium signaling, and defense responses downstream of FLS2; upon PAMP recognition, first phosphorylated by FLS2 and SIK1 prior to being monoubiquitinated by ATL44/RHA3A and ATL45/RHA3B at the plasma membrane, then internalized dynamically into endocytic compartments together with FLS2. Acts additively with PBL1 in PTI defenses. 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. 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. Involved in ethylene signaling. Destabilizes EIN3, the key transcription activator in ethylene signaling, and represses EIN3-dependent transcription. Acts as a negative regulator in brassinosteroid (BR) signaling. Functions in BR signaling by direct interaction with the BR receptor BRI1 cytosolic kinase domain. Required during SCOOP small peptides (e.g. SCOOP10 and SCOOP12) perception and signaling; receptor-like cytosolic kinases (RLCK) activated by BAK1/SERK3 and SERK4 coreceptors when associated with MIK2 upon the perception of SCOOP peptides.
Subcellular location: Cell membrane {ECO:0000269|PubMed:16339855, ECO:0000269|PubMed:26021844, ECO:0000269|PubMed:29649442, ECO:0000269|Ref.20}; Lipid-anchor {ECO:0000269|PubMed:16339855, ECO:0000269|PubMed:26021844}. Endosome membrane {ECO:0000269|Ref.20}; Lipid-anchor {ECO:0000269|PubMed:16339855, ECO:0000269|PubMed:26021844}. Nucleus {ECO:0000269|PubMed:29649442}. Note=Linked to the plasma membrane when inactivated, but moves to the nucleus upon pathogen-mediated activation by phosphorylation (PubMed:29649442). Internalized dynamically into endocytic compartments upon the recognition of microbe-associated molecular patterns (MAMPs, e.g. flg22), when monoubiquitinated after phosphorylation and subsequent dissociation of the FLS2/BIK1 complex (Ref.20). {ECO:0000269|PubMed:29649442, ECO:0000269|Ref.20}.
Interaction partners:
- Leucine-rich repeat receptor-like protein kinase PEPR1
- BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1
- Extra-large guanine nucleotide-binding protein 2
- Respiratory burst oxidase homolog protein D
- LRR receptor-like serine/threonine-protein kinase EFR
- Guanine nucleotide-binding protein subunit beta
- Elongation factor Tu, chloroplastic
- Probable protein phosphatase 2C 38
- Protein BRASSINOSTEROID INSENSITIVE 1
- Guanine nucleotide-binding protein subunit gamma 1
Sequence:
MGSCFSSRVKADIFHNGKSSDLYGLSLSSRKSSSTVAAAQKTEGEILSSTPVKSFTFNELKLATRNFRPDSVIGEGGFGCVFKGWLDESTLTPTKPGTGLVIAVKKLNQEGFQGHREWLTEINYLGQLSHPNLVKLIGYCLEDEHRLLVYEFMQKGSLENHLFRRGAYFKPLPWFLRVNVALDAAKGLAFLHSDPVKVIYRDIKASNILLDADYNAKLSDFGLARDGPMGDLSYVSTRVMGTYGYAAPEYMSSGHLNARSDVYSFGVLLLEILSGKRALDHNRPAKEENLVDWARPYLTSKRKVLLIVDNRLDTQYLPEEAVRMASVAVQCLSFEPKSRPTMDQVVRALQQLQDNLGKPSQTNPVKDTKKLGFKTGTTKSSEKRFTQKPFGRHLV