| Autor: |
Nastainczyk, Wolfgang, Rohrkasten, Axel, Sieber, Manfred, Rudolph, Claus, Schachtele, Christophe, Marme, Dieter, Hofmann, Franz |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 11/16/87, Vol. 169 Issue 1, p137-142, 6p |
| Abstrakt: |
The dihydropyridine receptor purified from rabbit skeletal muscle contains three proteins of 165, 55 and 32 kDa. cAMP kinase and protein kinase C phosphorylate the 165-kDa and the 55-kDa proteins. At identical concentrations of each protein kinase, cAMP kinase phosphorylates the I 65-kDa protein faster than the 55-kDa protein. Protein kinase C phosphorylates preferentially the 55-kDa protein, cAMP kinase incorporates up to 1.6 mol phosphate/mol protein into the I 65-kDa protein and I mol/mol into the 55-kDa protein upon prolonged incubation. At a physiological concentration of cAMP kinase 1 mol phosphate is incorporated/mol I 65-kDa protein within 10 mm, suggesting a physiological role of this phosphorylation. Protein kinase C incorporates up to I mol phosphate/mol into the 55-kDa protein and less than 1 mol/mol into the I 65-kDa protein. Tryptic phosphopeptide analysis reveals that cAMP kinase phosphorylates two distinct peptides in the 165-kDa protein, whereas protein kinase C phosphorylates a single peptide in the 165-kDa protein, cAMP kinase and protein kinase C phosphorylate three and two peptides in the 55-kDa protein, respectively. Mixtures of the tryptic phosphopeptides derived from the 165-kDa and 55-kDa proteins elute according to the composite of the two elution profiles. These results suggest that the 165-kfla protein, which contains the binding sites for each class of calcium channel blockers and the basic calcium-conducting structure, is a specific substrate for cAMP kinase. The 55- kDa protein apparently contains sites preferentially phosphorylated by protein kinase C. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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