A PHORBOL ESTER RECEPTOR PROTEIN-KINASE, NPKC-ETA, A NEW MEMBER OF THE PROTEIN-KINASE-C FAMILY PREDOMINANTLY EXPRESSED IN LUNG AND SKIN

作者：OSADA S^*; MIZUNO K; SAIDO TC; AKITA Y; SUZUKI K; KUROKI T; OHNO S

来源：Journal of Biological Chemistry, 1990, 265(36): 22434-22440.

Protein kinase C (PKC)-related cDNA clones isolated from mouse epidermis cDNA library encoded a 78-kDa protein, nPKC-eta. nPKC-eta-contains a characteristic cysteine-rich repeat sequence (C1 region) and a protein kinase domain sequence (C3 region), both of which are conserved among PKC family members. However, nPKC-eta-lacks a putative CA2+ binding region (C2 region) that is seen in conventional pkcS (alpha, beta-I, beta-II, gamma), but not in novel PKCs (nPKC-delta, -epsilon, -zeta). nPKC-eta shows the highest sequence similarity to nPKC-epsilon (598.4% identity). The similarity extends to the NH2-terminal sequence (E region) which corresponds to one of the divergent regions (D1 region). Northern blot analysis showed that the mRNA for nPKC-eta is highly expressed in the lung and skin but, in contrast to other members of the PKC family, only slightly expressed in the brain. n-PKC-eta expressed in COS cells shows phorbol ester binding activity with a similar affinity to nPKC-epsilon. Antiserum raised against a COOH-terminal peptide of nPKC-eta identified an 82-kDa protein in mouse lung extract as well as in an extract from COS cells transfected with the nPKC-eta-cDNA expression plasmid. Autophosphorylation of nPKC-eta immunoprecipitated with the specific antiserum was observed, indicating that nPKC-eta is a protein kinase. These results clearly demonstrate the existence and the possible importance of nPKC-eta as a member of the phorbol ester receptor/protein kinase, PKC, family.

• 出版日期1990-12-25
• 单位河北医科大学