Localization study of diacylglycerol-responsive protein kinase C isoforms in HeLa cells

초록

Protein kinase C (PKC), a family of multi-gene protein kinases has long been known to be translocated to the particular cellular compartments in response to DAG or its analog phorbol esters. We used C-terminal green fluorescent protein (GFP) fusion proteins of PKC isoforms to visualize the subcellular distribution of individual PKC isoforms. Intracellular localization of PKC-GFP proteins was monitored by fluorescence microscopy after transient transfection of PKC-GFP expression vectors in the HeLa cells. In unstimulated HeLa cells, all PKC isoforms were found to be distributed throughout the cytoplasm with a few exceptions. PKCtheta was mostly localized to the Golgi, and PKCgamma, PKCdelta and PKCeta showed cytoplasmic distribution with Golgi localization. DAG analog TPA induced translocation of PKC-GFP to the plasma membrane. PKCalpha, PKCeta and PKCtheta were also localized to the Golgi in response to TPA. These results suggest that specific PKC isoforms are translocated to different intracellular sites and exhibit distinct biological effects.