Intracellular distribution of phospholipase C gamma 1 in cell lines with different levels of transformation.

Abstract

The intracellular localization of phospholipase C gamma 1 (PLC gamma 1) was studied in cell lines with different levels of cell transformation. Immunofluorescence analysis of cell lines with differently organized actin cytoskeletons (A431 cells, HeLa cells, mouse hepatoma MH 22A, Zajdela ascitic hepatoma, primary human embryo skin and lung fibroblasts) gave evidence that PLC gamma 1 is colocalized only with cortical actin and not with stress fibers. Coimmunoprecipitation experiments indicated that PLC gamma 1 was bound to actin in all cell lines investigated. Further, the nuclei of highly transformed cell lines (A431 cells, HeLa cells, mouse hepatoma MH 22A, rat Zajdela ascitic hepatoma) were labeled with the anti-PLC gamma 1 antibody. In contrast, PLC gamma 1 was not observed in the nuclei of primary human embryo skin or lung fibroblasts. Since PLC gamma 1 exists only in the nuclei of highly transformed cell lines, we propose that the distinctive intracellular localization of PLC gamma 1 in normal and highly transformed cell lines may reflect differences in cell signaling systems and mitogenic cell signal transduction.