Localization of phosphatidylinositol 4-kinase isoenzymes in rat liver plasma membrane domains.

摘要: The presence of different isoenzymes phosphatidylinositol 4-kinase in isolated rat liver plasma membranes and their further distribution membrane domains was examined. Both wortmannin-sensitive -insensitive PtdIns activities were detected highly purified obtained by aqueous two-phase affinity partitioning. enzyme identified as the 230 kDa isoform Western blotting, whereas 92 not membranes. apparent molecular weights these isoforms 205 105 on SDS polyacrylamide gel electrophoresis, but approximately 500 respectively filtration, suggesting that both enzymes either are dimers or composed heterologous subunits. Approximately 25% total isoenzyme present liver, only ca 5% wortmannin-insensitive one, associated with fraction. Plasma a combination sucrose Nycodenz gradient centrifugations. blood sinusoidal domain, bile canalicular also found lateral this latter material. functional implications regions discussed.