Phospholipid-Sensitive Ca2+-Dependent Protein Kinase Preferentially Phosphorylates Serine-115 of Bovine Myelin Basic Protein |
| |
| Authors: | R. Scott Turner,C.-H. Jen Chou&dagger ,Gonzalo J. Mazzei,Philip Dembure,&Dagger ,J. F. Kuo |
| |
| Affiliation: | Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.;Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.;Department of Pediatrics (Division of Medical Genetics), Emory University School of Medicine, Atlanta, Georgia, U.S.A. |
| |
| Abstract: | Phospholipid-sensitive Ca2+ -dependent protein kinase (PL-Ca-PK) and cyclic AMP-dependent protein kinase (A-PK) both preferentially phosphorylated serine residues of bovine myelin basic protein (MBP). Tryptic peptide maps of MBP phosphorylated by PL-Ca-PK or A-PK, however, revealed different phosphopeptides, suggesting a difference in the intramolecular substrate specificity for the two enzymes. Serine-115 of MBP, in the sequence (-Arg-Phe-Ser(115)-Trp-), was found to be a preferred and probably major phosphorylation site for PL-Ca-PK. Because serine-115 of bovine MBP corresponds to serine-113 of rabbit MBP, an in vivo phosphorylation site reported by Martenson et al. (1983), and PL-Ca-PK is present at a very high level in brain and myelin, it is suggested that the enzyme may be responsible for the in vivo phosphorylation of this and other sites in MBP. |
| |
| Keywords: | Phosphorylation site Myelin basic protein Protein kinase |
|
|
