Multiple isoforms of a protein kinase C inhibitor (KCIP-1/14-3-3) from sheep brain. Amino acid sequence of phosphorylated forms.
A potent inhibitor of protein kinase C (PKC), inhibitor protein-1 (KCIP-1), isolated from sheep brain has been shown to consist of eight isoforms by reverse-phase HPLC. Direct protein sequence analysis has revealed these to be the same as those of 14-3-3 protein, described as an activator of tyrosine and tryptophan hydroxylases involved in neurotransmitter biosynthesis. The N-termini of KCIP-1 isoforms were shown to be acetylated, and secondary structure predictions revealed a high degree of alpha-helix with an amphipathic nature. KCIP-1 showed no inhibitory activity towards protein kinase M (the catalytic fragment of PKC) and had no effect on the activities of three other protein kinases, cAMP-dependent protein kinase, Ca2+/calmodulin-dependent protein kinase II and casein kinase 2. Four forms of KCIP-1 were shown to be substrates for PKC in vitro, but none were phosphorylated by the other protein kinases mentioned above.
Toker
A
A
Laboratory of Protein Structure, National Institute for Medical Research, Mill Hill, London, England.
Sellers
L A
LA
Amess
B
B
Patel
Y
Y
Harris
A
A
Aitken
A
A
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002851:Chromatography, High Pressure Liquid; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D011494:Protein Kinases / Q000378:metabolism; D016415:Sequence Alignment; D012756:Sheep; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D003432:Cross-Linking Reagents; D009419:Nerve Tissue Proteins; D014446:Tyrosine 3-Monooxygenase; D011494:Protein Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases