Hirai Takaaki, Chida Kazuhiro
Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657.
J Biochem. 2003 Jan;133(1):1-7. doi: 10.1093/jb/mvg017.
The zeta isotype of protein kinase C (PKCzeta) is a member of the atypical PKC subfamily and has been widely implicated in the regulation of cellular functions. Increasing evidence from studies using in vitro and in vivo systems points to PKCzeta as a key regulator of critical intracellular signaling pathways induced by various extracellular stimuli. The major activation pathway of PKCzeta depends on phosphatidylinositol (PI)-3,4,5-trisphosphate (PIP(3)), which is mainly produced by PI-3 kinase. 3'-PI-dependent protein kinase 1, which binds with high affinity to PIP(3), phosphorylates and activates PKCzeta. Many studies demonstrated the involvement of PKCzeta in the mitogen-activated protein kinase cascade, transcriptional factor NFkappaB activation, ribosomal S6-protein kinase signaling, and cell polarity. An important molecular event in a cell is the association of PKCzeta with other signaling molecules, as well as scaffold proteins, to form large complexes that regulate their pathways. The understanding of the mechanisms underlying PKCzeta-mediated control of intracellular signaling is beginning to provide important insights into the roles of PKCzeta in various cells.
蛋白激酶C的ζ亚型（PKCζ）是非典型蛋白激酶C亚家族的成员，在细胞功能调节中具有广泛作用。来自体外和体内系统研究的越来越多证据表明，PKCζ是各种细胞外刺激诱导的关键细胞内信号通路的关键调节因子。PKCζ的主要激活途径依赖于磷脂酰肌醇（PI）-3,4,5-三磷酸（PIP(3)），其主要由PI-3激酶产生。与PIP(3)具有高亲和力结合的3'-PI依赖性蛋白激酶1使PKCζ磷酸化并激活。许多研究表明PKCζ参与丝裂原活化蛋白激酶级联反应、转录因子NFκB激活、核糖体S6蛋白激酶信号传导和细胞极性。细胞中的一个重要分子事件是PKCζ与其他信号分子以及支架蛋白结合，形成调节其信号通路的大复合物。对PKCζ介导的细胞内信号控制机制的理解开始为PKCζ在各种细胞中的作用提供重要见解。
