Abstract The phosphorylation of specific membrane proteins by endogenous protein kinase in synaptic membrane fractions from rat cerebrum has been studied using the technique of acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The endogenous phosphorylation of two specific membrane proteins was found to be regulated by adenosine 3':5'-monophosphate (cyclic AMP). The minimal molecular weights of these proteins were determined, by gel electrophoresis in the presence of sodium dodecyl sulfate, to be 86,000 (Protein I) and 48,000 (Protein II). The endogenous phosphorylation of Protein I and Protein II was stimulated by cyclic AMP in the presence of magnesium ions. Approximately 80% and 75% of the 32P incorporated into Protein I and Protein II, respectively, was found in phosphoserine. The concentration of cyclic AMP required for maximal stimulation of the phosphorylation of both Protein I and Protein II was approximately 5 x 10-6 m. Guanosine 3':5'-monophosphate had no significant effect, at concentrations up to 10-4 m, on the phosphorylation of either of these proteins. The endogenous phosphorylation occurred rapidly, the phosphorylation of both Protein I and Protein II reaching maximal levels within 5 sec. After reaching a maximal level of phosphorylation, Protein II underwent rapid dephosphorylation. The cyclic AMP-stimulated endogenous phosphorylation of a protein corresponding in position on acrylamide gel electrophoresis to Protein I was also observed in membrane fractions prepared from other neural tissues known to contain synapses, but membrane fractions prepared from several neural and non-neural tissues devoid of synapses, including lingual nerve, lung, liver, spleen, and kidney, all failed to reveal cyclic AMP-dependent phosphorylation of a protein band corresponding in position to Protein I. In contrast, cyclic AMP-dependent phosphorylation of a protein band corresponding in position to Protein II was observed in several neural and non-neural tissues. The results are compatible with the hypothesis that the mediation of certain types of synaptic transmission may involve regulation by cyclic AMP of the level of phosphorylation of specific protein constituents of the synaptic membranes.
Regulation of endogenous phosphorylation of specific proteins in synaptic membrane fractions from rat brain by adenosine 3':5'-monophosphate.
Published 1973 in Journal of Biological Chemistry
ABSTRACT
PUBLICATION RECORD
- Publication year
1973
- Venue
Journal of Biological Chemistry
- Publication date
1973-12-10
- Fields of study
Biology, Medicine, Chemistry
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
- No claims are published for this paper.
CONCEPTS
- No concepts are published for this paper.
REFERENCES
Showing 1-33 of 33 references · Page 1 of 1