Abstract
To study enzymatic activity and activation conditions of the recently identified novel protein kinase C mu (PKC mu) subtype, epitope tagged PKC mu was propagated in the baculovirus expression system and was purified to homogeneity. PKC mu displays high affinity phorbol ester binding (Kd=7 nM) resulting in enhanced phosphatidylserine-dependent kinase activity. From various lipid second messengers known to activate PKCs only diacylglycerol and PtdIns-4,5-P2, were found to promote PKC mu kinase activity. Two peptides derived from the glycogen synthase, GS-peptide and syntide 2, were found to be phosphorylated efficiently in vitro. MARCKS (myristoylated alanine-rich C-kinase substrate) served as an in vitro substrate for PKC mu too. However, in contrast to other PKCs, a peptide derived from the MARCKS phosphorylation domain is phosphorylated only at serine 156, and not at serines 152 and 163, implicating a differential regulation by PKC mu.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Baculoviridae
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Electrophoresis, Polyacrylamide Gel
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Enzyme Activation
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Genetic Vectors
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Humans
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Insecta
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Intracellular Signaling Peptides and Proteins*
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Isoenzymes / biosynthesis
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Isoenzymes / isolation & purification
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Isoenzymes / metabolism*
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Kinetics
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Membrane Proteins*
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Molecular Sequence Data
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Molecular Weight
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Myristoylated Alanine-Rich C Kinase Substrate
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Oligopeptides / metabolism
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Phorbol 12,13-Dibutyrate / metabolism
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Phosphorylation
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Protein Kinase C / biosynthesis
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Protein Kinase C / isolation & purification
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Protein Kinase C / metabolism*
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Proteins / metabolism
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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Substrate Specificity
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Transfection
Substances
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Intracellular Signaling Peptides and Proteins
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Isoenzymes
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MARCKS protein, human
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Membrane Proteins
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Oligopeptides
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Proteins
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Recombinant Proteins
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Myristoylated Alanine-Rich C Kinase Substrate
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Phorbol 12,13-Dibutyrate
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kemptide
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Protein Kinase C