title: Alternative complex formation of the Ca-regulated protein kinase CIPK1 controls abscisic acid-dependent and independent stress responses in Arabidopsis.
abstract: Intracellular release of calcium ions belongs to the earliest events in cellular stress perception. The molecular mechanisms integrating signals from different environmental cues and translating them into an optimized response are largely unknown. We report here the functional characterization of CIPK1, a protein kinase interacting strongly with the calcium sensors CBL1 and CBL9. Comparison of the expression patterns indicates that the three proteins execute their functions in the same tissues. Physical interaction of CIPK1 with CBL1 and CBL9 targets the kinase to the plasma membrane. We show that, similarly to loss of CBL9 function, mutation of either CBL1 or CIPK1 renders plants hypersensitive to osmotic stress. Remarkably, in contrast to the cbl1 mutant and similarly to the cbl9 mutant, loss of CIPK1 function impairs abscisic acid (ABA) responsiveness. We therefore suggest that, by alternative complex formation with either CBL1 or CBL9, the kinase CIPK1 represents a convergence point for ABA-dependent and ABA-independent stress responses. Based on our genetic, physiological and protein-protein interaction data, we propose a general model for information processing in calcium-regulated signalling networks.
authors.affiliation: Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
authors.forename: Cecilia
authors.initials: C
authors.lastname: D'Angelo
authors.forename: Stefan
authors.initials: S
authors.lastname: Weinl
authors.forename: Oliver
authors.initials: O
authors.lastname: Batistic
authors.forename: Girdhar K
authors.initials: GK
authors.lastname: Pandey
authors.forename: Yong Hwa
authors.initials: YH
authors.lastname: Cheong
authors.forename: Stefanie
authors.initials: S
authors.lastname: Schültke
authors.forename: Veronica
authors.initials: V
authors.lastname: Albrecht
authors.forename: Britta
authors.initials: B
authors.lastname: Ehlert
authors.forename: Burkhard
authors.initials: B
authors.lastname: Schulz
authors.forename: Klaus
authors.initials: K
authors.lastname: Harter
authors.forename: Sheng
authors.initials: S
authors.lastname: Luan
authors.forename: Ralph
authors.initials: R
authors.lastname: Bock
authors.forename: Jörg
authors.initials: J
authors.lastname: Kudla
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D015870:Gene Expression; D009997:Osmotic Pressure; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C514582:CBL9 protein, Arabidopsis; D002135:Calcium-Binding Proteins; C483419:calcineurin B-like protein 1, Arabidopsis; D000040:Abscisic Acid; C507144:CIPK1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases