title: A WNK kinase binds and phosphorylates V-ATPase subunit C.
abstract: WNK (with no lysine (K)) protein kinases are found in many eukaryotes and share a unique active site. Here, we report that a member of the Arabidopsis WNK family (AtWNK8) interacts with subunit C of the vacuolar H+-ATPase (V-ATPase) via a short C-terminal domain. AtWNK8 is shown to autophosphorylate intermolecularly and to phosphorylate Arabidopsis subunit C (AtVHA-C) at multiple sites as determined by MALDI-TOF MS analysis. Furthermore, we show that AtVHA-C and other V-ATPase subunits are phosphorylated when V1-complexes are used as substrates for AtWNK8. Taken together, our results provide evidence that V-ATPases are potential targets of WNK kinases and their associated signaling pathways.
authors.affiliation: Universität Tübingen, ZMBP-Plant Physiology, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Hong-Hermesdorf
authors.forename: Angela
authors.initials: A
authors.lastname: Brüx
authors.forename: Ardina
authors.initials: A
authors.lastname: Grüber
authors.forename: Gerhard
authors.initials: G
authors.lastname: Grüber
authors.forename: Karin
authors.initials: K
authors.lastname: Schumacher
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000502:physiology; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D020798:Two-Hybrid System Techniques; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D017346:Protein Serine-Threonine Kinases; C508913:WNK8 protein, Arabidopsis; C505814:Det3 protein, Arabidopsis; D025262:Vacuolar Proton-Translocating ATPases