Phosphorylation of myelin basic protein and peptides by ganglioside-stimulated protein kinase.
Rabbit myelin basic protein (MBP) was phosphorylated by a ganglioside-stimulated protein kinase to a stoichiometry of 1.4 and 2.1 mol phosphate/mol MBP in the presence and absence of GTlb, respectively. Two-dimensional peptide mapping analyses revealed that two of the sites of phosphorylation were distinct from those catalyzed by cAMP-dependent protein kinase or protein kinase C. Phosphorylation of one of these sites by ganglioside-stimulated protein kinase was inhibited by GTlb, suggesting that the inhibitory effect of gangliosides on MBP phosphorylation may be substrate-directed. Although ganglioside-stimulated protein kinase did not phosphorylate MBP at a domain containing residues 82-117, a synthetic peptide Arg-Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys corresponding to residues 111-120 was phosphorylated by the kinase in a ganglioside-stimulated manner. These findings suggest that the conformation of MBP may be important in determining its phosphorylatability.
Chan
K F
KF
Laboratory of Experimental Neuropathology, NINDS, Bethesda, MD 20892.
D000595:Amino Acid Sequence; D005732:Gangliosides / Q000494:pharmacology*; D007700:Kinetics; D008969:Molecular Sequence Data; D004676:Myelin Basic Protein / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism*; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism*; D010748:Phosphopeptides / Q000302:isolation & purification; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D013379:Substrate Specificity
D005732:Gangliosides; D004676:Myelin Basic Protein; D009842:Oligopeptides; D010446:Peptide Fragments; D010748:Phosphopeptides; C016481:trisialoganglioside GT1; D011494:Protein Kinases