| 描述 | The Protein Kinase C (PKC) family of homologous serine/threonine protein kinases is involved in a number of processes, such as growth, differentiation, and cytokine secretion. At least eleven isozymes have been described. These proteins are products of multiple genes and alternative splicing. Conventional PKC (cPKC) subfamily members ( a,b , and γ isoforms) consists of a single polypeptide chain containing four conserved regions (C) and five variable regions (V). The N-terminal half containing C1, C2, V1, and V2 constitutes the regulatory domain and interacts with the PKC activators Ca2+, phospholipid, diacylglycerol, or phorbol ester. However, the the C2-like domains of novel PKC (nPKC) subfamily members (δ, ε, η, and θ isoforms) are Ca2+-independent. The atypical PKC (aPKC) subfamily members (ζ, ι, and μ isoforms) lack the C2 domain and are unique in that their activity is independent of diacylglycerols and phorbol esters. They also lack one repeat of the cysteine-rich sequences that are conserved in c PKC and nPKC members. The C-terminal region of PKC contains the catalytic domain. The PKC pathway represents a major signal transduction system that is activated following ligand-stimulation of transmembrane receptors by hormones, neurotransmitters, and growth factors. PKCα regulates a wide variety of functions such as cellular growth, apoptosis, cardiomyocyte function, and brain cognitive functions. The 3/PKC α monoclonal antibody recognizes PKCα , regardless of phosphorylation status, and has been reported to crossreact with PKCβ. |
