Intracellular receptors for activated protein kinase C. Identification of a binding site for the enzyme.
Protein kinase C (PKC) isozymes comprise a family of cytosolic enzymes that translocate to different intracellular sites on activation. We have recently characterized at least two intracellular receptor proteins for PKC (termed RACKs for receptors for activated C-kinase) in the Triton-insoluble material of the particulate fraction from neonatal rat heart. Here, we identify a sequence that appears to resemble the PKC binding site on these RACKs. A peptide (peptide I) with the sequence KGDYEKILVALCGGN bound PKC, and binding was markedly increased in the presence of PKC activators. Furthermore, peptide I inhibited PKC binding to RACKs in a dose-dependent manner. These data suggest that these RACKs have a common PKC binding sequence. Since peptide I inhibited PKC binding to RACKs in vitro, it may be a useful tool to inhibit PKC translocation and subsequent function in vivo.
Mochly-Rosen
D
D
Department of Neurology, University of California, San Francisco General Hospital 94110.
Khaner
H
H
Lopez
J
J
Smith
B L
BL
D000595:Amino Acid Sequence; D000818:Animals; D017302:Annexins; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D002135:Calcium-Binding Proteins / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D000075370:Receptors for Activated C Kinase; D012689:Sequence Homology, Nucleic Acid
D017302:Annexins; D002135:Calcium-Binding Proteins; D010455:Peptides; D000075370:Receptors for Activated C Kinase; C070301:peptide I; D011493:Protein Kinase C