Phosphorylation by protein kinase C of serine-23 of the alpha-1 subunit of rat Na+,K(+)-ATPase affects its conformational equilibrium
| Autor: | Anita Aperia, Angus C. Nairn, Stefan H. Larsson, Paul Greengard, Natalya U. Fedosova, Ninel S. Logvinenko, Mikael Esmann, Irina Dulubova |
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| Rok vydání: | 1996 |
| Předmět: |
Phosphopeptides
Protein Conformation Recombinant Fusion Proteins Protein subunit Molecular Sequence Data Biology Peptide Mapping Ca2+/calmodulin-dependent protein kinase Serine Animals Protein phosphorylation Amino Acid Sequence Enzyme Inhibitors Phosphorylation Na+/K+-ATPase Protein kinase A Protein Kinase C Protein kinase C Fluorescent Dyes Multidisciplinary Base Sequence Molecular biology Peptide Fragments Phosphoric Monoester Hydrolases Rats Biochemistry Molecular Probes Cyclin-dependent kinase complex Eosine Yellowish-(YS) Sodium-Potassium-Exchanging ATPase Research Article |
| Zdroj: | Aarhus University Logvinenko, N S, Dulubova, I, Fedosova, N, Larsson, S H, Nairn, A C, Esmann, M, Greengard, P & Aperia, A 1996, ' Phosphorylation by protein kinase C of serine-23 of the alpha-1 subunit of rat Na+,K(+)-ATPase affects its conformational equilibrium ', Proceedings of the National Academy of Sciences of the United States of America, vol. 93, no. 17, pp. 9132-9137 . |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Phosphorylation of the alpha-1 subunit of rat Na+,K(+)-ATPase by protein kinase C has been shown previously to decrease the activity of the enzyme in vitro. We have now undertaken an investigation of the mechanism by which this inhibition occurs. Analysis of the phosphorylation of recombinant glutathione S-transferase fusion proteins containing putative cytoplasmic domains of the protein, site-directed mutagenesis, and two-dimensional peptide mapping indicated that protein kinase C phosphorylated the alpha-1 subunit of the rat Na+,K(+)-ATPase within the extreme NH2-terminal domain, on serine-23. The phosphorylation of this residue resulted in a shift in the equilibrium toward the E1 form, as measured by eosin fluorescence studies, and this was associated with a decrease in the apparent K+ affinity of the enzyme, as measured by ATPase activity assays. The rate of transition from E2 to E1 was apparently unaffected by phosphorylation by protein kinase C. These results, together with previous studies that examined the effects of tryptic digestion of Na+,K(+)-ATPase, suggest that the NH2-terminal domain of the alpha-1 subunit, including serine-23, is involved in regulating the activity of the enzyme. |
| Databáze: | OpenAIRE |
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