Tobacco calcium-dependent protein kinases are differentially phosphorylated in vivo as part of a kinase cascade that regulates stress response
| Autor: | Tina Romeis, Anindita Seal, Raphael Demoulière, Ullrich Dubiella, Claus-Peter Witte, Nana F. Keinath |
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| Rok vydání: | 2010 |
| Předmět: |
Molecular Sequence Data
Arabidopsis Biochemistry Gene Expression Regulation Enzymologic Mass Spectrometry MAP2K7 Gene Expression Regulation Plant Tobacco ASK1 Protein phosphorylation c-Raf Amino Acid Sequence Phosphorylation Protein kinase A Molecular Biology MAPK14 biology Sequence Homology Amino Acid Autophosphorylation Cyclin-dependent kinase 2 Cell Biology Kinetics Phenotype biology.protein Mutagenesis Site-Directed Calcium Protein Kinases Signal Transduction |
| Zdroj: | The Journal of biological chemistry. 285(13) |
| ISSN: | 1083-351X |
| Popis: | In vivo phosphorylation sites of the tobacco calcium-dependent protein kinases NtCDPK2 and NtCDPK3 were determined in response to biotic or abiotic stress. Stress-inducible phosphorylation was exclusively located in the variable N termini, where both kinases were phosphorylated differentially despite 91% overall sequence identity. In NtCDPK2, serine 40 and threonine 65 were phosphorylated within 2 min after stress. Whereas Thr(65) is subjected to intra-molecular in vivo autophosphorylation, Ser(40) represents a target for a regulatory upstream protein kinase, and correct NtCDPK2 membrane localization is required for Ser(40) phosphorylation. NtCDPK3 is phosphorylated at least at two sites in the N terminus by upstream kinase(s) upon stress stimulus, first at Ser(54), a site not present in NtCDPK2, and also at a second undetermined site not identical to Ser(40). Domain swap experiments established that differential phosphorylation of both kinases is exclusively determined by the respective N termini. A cell death-inducing response was only observed upon expression of a truncated variant lacking the junction and calcium-binding domain of NtCDPK2 (VK2). This response required protein kinase activity and was reduced when subcellular membrane localization was disturbed by a mutation in the myristoylation and palmitoylation site. Our data indicate that CDPKs are integrated in stress-dependent protein kinase signaling cascades, and regulation of CDPK function in response to in vivo stimulation is dependent on its membrane localization. |
| Databáze: | OpenAIRE |
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