A calcium and calmodulin-dependent protein kinase present in differentiating Dictyostelium discoideum
| Autor: | John F. Wheldrake, Andrew J. Dunbar |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
biology
Calmodulin Cyclin-dependent kinase 2 Mitogen-activated protein kinase kinase Chromatography Agarose Microbiology Trifluoperazine MAP2K7 Molecular Weight Calmodulin dependent protein kinase Biochemistry Ca2+/calmodulin-dependent protein kinase Calcium-Calmodulin-Dependent Protein Kinases Genetics biology.protein Animals Dictyostelium Electrophoresis Polyacrylamide Gel c-Raf Phosphorylation Molecular Biology cGMP-dependent protein kinase Protein Kinases |
| Zdroj: | FEMS microbiology letters. 115(1) |
| ISSN: | 0378-1097 |
| Popis: | A protein kinase from Dictyostelium discoideum which phosphorylates the synthetic peptide, calmodulin-dependent protein kinase substrate (CDPKS, amino acid sequence: PLRRTLSVAA) and is stimulated by Ca2+/calmodulin is described. This is the first report of a protein kinase with these characteristics in D. discoideum. The enzyme was partially purified by Q-Sepharose chromatography. The protein kinase is very labile, and rapidly loses Ca2+/calmodulin-dependence upon standing at 4 degrees C, even in the presence of protease inhibitors, making further purification and characterisation difficult. In the active fractions, a 55 kDa polypeptide is labelled with [gamma-32P]ATP in vitro under conditions in which intramolecular rather than intermolecular reactions are favoured. The phosphorylation of this peptide is stimulated in the presence of Ca2+ and calmodulin but not Ca2+ alone. Ca2+/calmodulin-dependent stimulation is inhibited in the presence of the calmodulin antagonist, trifluoperazine (TFP). It is proposed that the 55 kDa polypeptide may represent the autophosphorylated form of the enzyme. |
| Databáze: | OpenAIRE |
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