Mochly-Rosen D, Henrich C J, Cheever L, Khaner H, Simpson P C
Department of Neurology, University of California, San Francisco.
Cell Regul. 1990 Aug;1(9):693-706. doi: 10.1091/mbc.1.9.693.
Protein kinase C (PKC)1 isozymes comprise a family of related cytosolic kinases that translocate to the cell particulate fraction on stimulation. The activated enzyme is thought to be on the plasma membrane. However, phosphorylation of protein substrates occurs throughout the cell and is inconsistent with plasma membrane localization. Using an isozyme-specific monoclonal antibody we found that, on activation, this PKC isozyme translocates to myofibrils in cardiac myocytes and to microfilaments in fibroblasts. Translocation of this activated PKC isozyme to cytoskeletal elements may explain some of the effects of PKC on cell contractility and morphology. In addition, differences in the translocation site of individual isozymes--and, therefore, phosphorylation of different substrates localized at these sites--may explain the diverse biological effects of PKC.
蛋白激酶C（PKC）1同工酶是一族相关的胞质激酶，在受到刺激时会转位至细胞颗粒部分。活化的酶被认为位于质膜上。然而，蛋白质底物的磷酸化在整个细胞内发生，这与质膜定位不一致。使用一种同工酶特异性单克隆抗体，我们发现，在活化时，这种PKC同工酶会转位至心肌细胞的肌原纤维以及成纤维细胞的微丝。这种活化的PKC同工酶向细胞骨架成分的转位可能解释了PKC对细胞收缩性和形态的一些影响。此外，各个同工酶转位位点的差异——以及因此位于这些位点的不同底物的磷酸化——可能解释了PKC的多种生物学效应。
