Phospholipase C, delta 4 Adenovirus (Ad-PLC (delta 4) )

Phospholipase C gamma1 (PLC gamma1), a phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2) -specific phosphodiesterase plays a critical 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. A total of nine mammalian PLC isozymes have been described (PLC beta1, PLC beta2, PLC beta3, PLC beta4, PLC gamma1, PLC gamma2, PLC zeta1, PLC delta2 and PLC epsilon) with molecular weights ranging from 85 to 255 kDa. The gamma-type enzymes are unique in that they contain SH2 and SH3 domains. Moreover, the two gamma-type enzymes, but not the beta and zeta isozymes, are subject to activation by a number of protein tyrosine kinases, which associate with SH2 domains and induce their activation by phosphorylation. In contrast, activation of PLC beta1, PLC beta2 and PLC beta3 is mediated by the alpha subunits of the Gq class of heterotrimeric G proteins and by certain G protein beta/gamma subunits. PLC-L (for PLC-deleted in lung carcinoma) plays a role in inositol phospholipid-based intracellular signaling and contributes to the progression of human lung carcinoma.