Abstract
Inositol phospholipids hydrolysis is coupled to receptor activation involved in the elevation of intracellular Ca2+and protein kinase C. Recently, this signal transduction system has been paid attention, since this system mediates not only hormonal effects but also cell growth. cell transformation and differentiaton.
In this signal transduction system, guanine nucleotide binding protein.makes important roles in the hydrolysis of inositol phospholipids through lowering Ca2+ for phospholipase C activation. The hydrolysis of phosphatidylinositol 4, 5-bisphoshpate to inositol 1.4, 5-trisphosphate (IP3) and diacylglycerol (DG) produces two important second messengers. IP3 can release Ca2+ from intracellular Ca2+ store and DG can activate protein kinase C. Therefore, this signal transduction system activates two kinases, Ca2+/calmodulin kinase and protein kinase C, which leads to various cellular responses.
