A novel phorbol ester receptor/protein kinase, nPKC, distantly related to the protein kinase C family.
Protein kinase C (PKC)-related cDNA clones encode an 84 kd protein, nPKC. nPKC contains a cysteine-rich repeat sequence homologous to that seen in conventional PKCs (alpha, beta I, beta II, and gamma), which make up a family of 77-78 kd proteins with closely related sequences. nPKC, when expressed in COS cells, confers increased high-affinity phorbol ester receptor activity to intact cells. Antibodies raised against nPKC identified a 90 kd protein in rabbit brain extract as well as in extracts from COS cells transfected with the cDNA construct. nPKC shows protein kinase activity that is regulated by phospholipid, diacylglycerol, and phorbol ester but is independent of Ca2+. The structural and enzymological characteristics of nPKC clearly distinguish it from conventional PKCs, which until now have been the only substances believed to mediate the various effects of diacylglycerol and phorbol esters. These results suggest an additional signaling pathway involving nPKC.
Ohno
S
S
Department of Molecular Biology, Tokyo Metropolitan Institute of Medical Science, Japan.
Akita
Y
Y
Konno
Y
Y
Imajoh
S
S
Suzuki
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005796:Genes; D008969:Molecular Sequence Data; D010703:Phorbol Esters / Q000378:metabolism; D011493:Protein Kinase C / Q000235:genetics* / Q000378:metabolism; D011817:Rabbits; D011955:Receptors, Drug; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010703:Phorbol Esters; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D004247:DNA; D011493:Protein Kinase C