EFFECT OF H-RAS PROTEINS ON THE ACTIVITY OF POLYPHOSPHOINOSITIDE PHOSPHOLIPASE-C IN HL60 MEMBRANES

The present study was undertaken to investigate whether purified ras protein can effect the activity of polyphosphoinositide specific phospholipase C in a cell-free membrane system. For this purpose we used homogenous preparations of the proto-oncogenic (H-rasgly12) and the oncogenic (H-rasval12) forms of the human H-ras proteins and membranes prepared from the human leukemic HL60 cells. We demonstrate that both the proto-oncogenic and the oncogenic form of H-ras proteins stimulate phospholipase C activity only when coupled to non-hydrolysable analogues of GTP. © 1990.