title: Calcium-dependent modulation and plasma membrane targeting of the AKT2 potassium channel by the CBL4/CIPK6 calcium sensor/protein kinase complex.
abstract: Potassium (K(+)) channel function is fundamental to many physiological processes. However, components and mechanisms regulating the activity of plant K(+) channels remain poorly understood. Here, we show that the calcium (Ca(2+)) sensor CBL4 together with the interacting protein kinase CIPK6 modulates the activity and plasma membrane (PM) targeting of the K(+) channel AKT2 from Arabidopsis thaliana by mediating translocation of AKT2 to the PM in plant cells and enhancing AKT2 activity in oocytes. Accordingly, akt2, cbl4 and cipk6 mutants share similar developmental and delayed flowering phenotypes. Moreover, the isolated regulatory C-terminal domain of CIPK6 is sufficient for mediating CBL4- and Ca(2+)-dependent channel translocation from the endoplasmic reticulum membrane to the PM by a novel targeting pathway that is dependent on dual lipid modifications of CBL4 by myristoylation and palmitoylation. Thus, we describe a critical mechanism of ion-channel regulation where a Ca(2+) sensor modulates K(+) channel activity by promoting a kinase interaction-dependent but phosphorylation-independent translocation of the channel to the PM.
authors: Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, 48149 Münster, Germany.
authors: Katrin
authors: K
authors: Held
authors: François
authors: F
authors: Pascaud
authors: Christian
authors: C
authors: Eckert
authors: Pawel
authors: P
authors: Gajdanowicz
authors: Kenji
authors: K
authors: Hashimoto
authors: Claire
authors: C
authors: Corratgé-Faillie
authors: Jan Niklas
authors: JN
authors: Offenborn
authors: Benoît
authors: B
authors: Lacombe
authors: Ingo
authors: I
authors: Dreyer
authors: Jean-Baptiste
authors: JB
authors: Thibaud
authors: Jörg
authors: J
authors: Kudla
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D010641:Phenotype; D010766:Phosphorylation; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D015398:Signal Transduction
chemical_list: C097485:AKT2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D015221:Potassium Channels; C112941:SOS3 protein, Arabidopsis; C562040:CIPK6 protein, Arabidopsis; D011494:Protein Kinases; D002118:Calcium