<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator"^^ . "The phytohormone abscisic acid (ABA) plays a major role in plant development and plant adaptation to both biotic and abiotic stressors. Key processes regulated by ABA include dormancy, seed germination, early seedling development and stomatal closure. To coordinate these functions an extensive network of signal transducers is necessary. In recent years knowledge of the ABA signal transduction pathway in Arabidopsis has advanced rapidly and provided a core signaling module which forms the basis for early ABA signaling events. Three major protein classes are involved: ABA binding proteins of the PYR/PYL family, Protein Phosphatases 2Cs (PP2Cs) and SNF1-related protein kinase 2s (SnRK2s). Specific recognition of the hormone is mediated by PYR/PYL receptors. Once ABA is bound to the receptor, PYR/PYLs inhibit the central negative regulators, PP2Cs, thus allowing the activation of downstream SnRK2s which positively regulate ABA responses. Reversible post-translational modification as a result of the antagonistic action of protein kinases and protein phosphatases is crucial to the ABA core signaling pathway. However, except for SnRK2s information on additional protein kinases is limited. Our work provides evidence that, opposite SnRK2s, a kinase of the WNK family is a new component of the ABA signaling pathway. The Arabidopsis WNK family consists of 11 serine/threonine protein kinases exhibiting a characteristic replacement of a unique lysine residue in the catalytic domain, hence the name WNK [With No K (Lysine)]. Phenotypic analysis of wnk8 mutants, exhibiting altered postgermination growth in response to ABA, indicated that AtWNK8 could be involved in ABA signaling. Genetic as well as direct interaction studies proved that AtWNK8 and a member of the PP2C family of protein phosphatases (AtPP2CA) interact. Biochemical data suggested that AtWNK8 activity is directly regulated by AtPP2CA, and, in turn, the ABA receptor AtPYR1 is phosphorylated by AtWNK8. In summary, our data support a role for the protein kinase AtWNK8 in ABA signaling. Opposite the main positive regulators SnRK2, we propose AtWNK8 as a new negative regulator closely associated with the members of the core ABA signaling module. "^^ . "2012" . . . . . . . . "Esther C."^^ . "Jawurek"^^ . "Esther C. Jawurek"^^ . . . . . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator (PDF)"^^ . . . "Dissertation_E.Jawurek.pdf"^^ . . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Extending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #13636 \n\nExtending the ABA signaling network: The protein kinase AtWNK8 is a negative regulator\n\n" . "text/html" . . . "570 Biowissenschaften, Biologie"@de . "570 Life sciences"@en . .