Phosphoinositide-specific phospholipase C (PLC) plays a crucial role in the initiation of receptor mediated signal transduction through the generation of the two second messengers, inositol 1,4,5-triphosphate and diacylglycerol from phosphatidylinositol 4,5-bisphosphate. There are many mammalian PLC isozymes, including PLC ?1, PLC ?2, PLC ?3, PLC ?4, PLC ?1, PLC ?2, PLC ?1, PLC ?2 and PLC ?. PLC ?1 is widely distributed in bronchiolar epithelium, type I and II pneumocytes and fibroblasts of the interstitial tissue. Actinregulatory protein Villin is tyrosine phosphorylated and associates with PLC ?1 in the brush border of intestinal epithelial cells. Villin regulates PLC ?1 activity by modifying its own ability to bind phosphatidylinositol 4,5-biphosphate. PLC ?1 binds ?1?1 Integrin and modulates ?1?1 Integrin-specific adhesion. PLC ?1 and Ca2+ play a direct role in VEGF-regulated endothelial growth, however this signaling pathway is not linked to FGF-mediated effects in primary endothelial cells.