Myristoylated alanine-rich C kinase substrate (MARCKS), a major protein kinase C substrate, is an in vivo substrate of proline-directed protein kinase(s). A mass spectroscopic analysis of the post-translational modifications.
Myristoylated alanine-rich C kinase substrate (MARCKS), a major in vivo substrate protein of protein kinase C, isolated from calf brain contains various species phosphorylated to different degrees. To establish the in vivo phosphorylation sites, the protein was digested with lysyl endoprotease, and the digests were analyzed by the capillary high performance liquid chromatography interfaced on-line to an electrospray mass spectrometer. Six out of 17 peptides were found to be phosphorylated. Of the 7 phosphorylated serine residues identified by Edman degradation, only 1 was within the known phosphorylation domain by protein kinase C. All the other phosphorylated serine residues originated from the N-terminal half of the molecule and were immediately followed by proline. Therefore, MARCKS, a major in vivo substrate of protein kinase C, is also an in vivo substrate of proline-directed protein kinase(s) such as mitogen-activated protein kinase or Cdk5 kinase.
Division of Biomedical Polymer Science, Fujita Health University, Aichi, Japan.
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Taniguchi
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Manenti
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Suzuki
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Titani
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D002846:Chromatography, Affinity; D047908:Intracellular Signaling Peptides and Proteins; D013058:Mass Spectrometry / Q000379:methods; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D038461:Proline-Directed Protein Kinases; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism; D013379:Substrate Specificity
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D011506:Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D038461:Proline-Directed Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D012697:Serine Endopeptidases; C036813:lysyl endopeptidase