Hormonal Regulation of Phospholipid Metabolism via G-proteins II: PLA2 and Inhibitory Regulation of PLC
Lipid derivatives play a major role as second messengers. A large body of evidence has accumulated on the mechanisms leading to their formation and on their role in cell regulation (reviewed in Dennis et al. 1991). They are formed by the action of different phospholipases (A2, C, D) acting on membrane phospholipids. Of particular physiological relevance has been the elucidation of the hormonal regulation of these enzymes. A large number of receptors for hormones and neurotransmitters are coupled to cellular phospholipases and regulate the cytosolic levels of second messengers such as Ca2+, diacylglycerol, inositol trisphosphate, and arachidonic acid. The activation of phospholipases can be indirectly induced by a receptormediated increase in cytosolic Ca2+, or it can be due to the activation of a heterotrimeric GTP-binding (G) protein directly coupled to the enzyme.
KeywordsDopamine Adenosine Retina Prostaglandin Thrombin
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