Heterologous expression and biochemical characterization of two calcium-dependent protein kinase isoforms CaCPK1 and CaCPK2 from chickpea
In plants, calcium-dependent protein kinases (CPKs) constitute a unique family of enzymes consisting of a protein kinase catalytic domain fused to carboxy-terminal autoregulatory and calmodulin-like domains. We isolated two cDNAs encoding calcium-dependent protein kinase isoforms (CaCPK1 and CaCPK2)...
| Veröffentlicht in: | Journal of plant physiology. - 1979. - 163(2006), 11 vom: 28. Nov., Seite 1083-93 |
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| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2006
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| Zugriff auf das übergeordnete Werk: | Journal of plant physiology |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Calmodulin Isoenzymes Plant Proteins Recombinant Proteins Protein Kinases EC 2.7.- |
| Zusammenfassung: | In plants, calcium-dependent protein kinases (CPKs) constitute a unique family of enzymes consisting of a protein kinase catalytic domain fused to carboxy-terminal autoregulatory and calmodulin-like domains. We isolated two cDNAs encoding calcium-dependent protein kinase isoforms (CaCPK1 and CaCPK2) from chickpea. Both isoforms were expressed as fusion proteins in Escherichia coli. Biochemical analyses have identified CaCPK1 and CaCPK2 as Ca(2+)-dependent protein kinases since both enzymes phosphorylated themselves and histone III-S as substrate only in the presence of Ca(2+). The kinase activity of the recombinant enzymes was calmodulin independent and sensitive to CaM antagonists W7 [N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide] and calmidazoilum. Phosphoamino acid analysis revealed that the isoforms transferred the gamma-phosphate of ATP only to serine residues of histone III-S and their autophosphorylation occurred on serine and threonine residues. These two isoforms showed considerable variations with respect to their biochemical and kinetic properties including Ca(2+) sensitivities. The recombinant CaCPK1 has a pH and temperature optimum of pH 6.8-8.6 and 35-42 degrees C, respectively, whereas CaCPK2 has a pH and temperature optimum of pH 7.2-9 and 35-42 degrees C, respectively. Taken together, our results suggest that CaCPK1 and CaCPK2 are functional serine/threonine kinases and may play different roles in Ca(2+)-mediated signaling in chickpea plants |
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| Beschreibung: | Date Completed 08.12.2006 Date Revised 11.03.2022 published: Print-Electronic GENBANK: AY312268, AY312269 Citation Status MEDLINE |
| ISSN: | 1618-1328 |