title: The Calcineurin B-like calcium sensors CBL1 and CBL9 together with their interacting protein kinase CIPK26 regulate the Arabidopsis NADPH oxidase RBOHF.
abstract: Stimulus-specific accumulation of second messengers like reactive oxygen species (ROS) and Ca(2+) are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal interrelation of Ca(2+) and ROS signaling are only beginning to emerge. NADPH oxidases of the respiratory burst oxidase homolog (RBOH) family are critical components contributing to the generation of ROS while Calcineurin B-like (CBL) Ca(2+) sensor proteins together with their interacting kinases (CIPKs) have been shown to function in many Ca(2+)- signaling processes. In this study, we identify direct functional interactions between both signaling systems. We report that the CBL-interacting protein kinase CIPK26 specifically interacts with the N-terminal domain of RBOHF in yeast two-hybrid analyses and with the full-length RBOHF protein in plant cells. In addition, CIPK26 phosphorylates RBOHF in vitro and co-expression of either CBL1 or CBL9 with CIPK26 strongly enhances ROS production by RBOHF in HEK293T cells. Together, these findings identify a direct interconnection between CBL-CIPK-mediated Ca(2+) signaling and ROS signaling in plants and provide evidence for a synergistic activation of the NADPH oxidase RBOHF by direct Ca(2+)-binding to its EF-hands and Ca(2+)-induced phosphorylation by CBL1/9-CIPK26 complexes.
authors: Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
authors: Maria Magdalena
authors: MM
authors: Drerup
authors: Kathrin
authors: K
authors: Schlücking
authors: Kenji
authors: K
authors: Hashimoto
authors: Prabha
authors: P
authors: Manishankar
authors: Leonie
authors: L
authors: Steinhorst
authors: Kazuyuki
authors: K
authors: Kuchitsu
authors: Jörg
authors: J
authors: Kudla
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology; D004789:Enzyme Activation; D057809:HEK293 Cells; D006801:Humans; D019255:NADPH Oxidases / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport
chemical_list: D029681:Arabidopsis Proteins; C514582:CBL9 protein, Arabidopsis; D002135:Calcium-Binding Proteins; C483419:calcineurin B-like protein 1, Arabidopsis; D019255:NADPH Oxidases; C584806:CIPK26 protein, Arabidopsis; D011494:Protein Kinases; D002118:Calcium