Stereospecificity of diacylglycerol for stimulus-response coupling in platelets.
In intact platelets, a permeable diacylglycerol having a 1,2-sn- but not 2,3-sn- configuration activated protein kinase C directly. In the presence of Ca2+-ionophore this diacylglycerol caused full activation of platelet release reaction. 1,3-Isomer was inactive. Among these isomers only 1,2-sn-diacylglycerol was converted rapidly to the corresponding phosphatidic acid in both intact and broken cell preparations. Thus, the diacylglycerol which functions in stimulus-response coupling possesses a 1,2-sn-glycerol backbone, and other isomers are not involved in the signal transduction through the protein kinase C pathway.
D001792:Blood Platelets / Q000378:metabolism*; D004075:Diglycerides / Q000097:blood* / Q000502:physiology; D005989:Glycerides / Q000097:blood*; D006801:Humans; D010712:Phosphatidic Acids / Q000097:blood; D010766:Phosphorylation; D011493:Protein Kinase C / Q000097:blood; D012701:Serotonin / Q000097:blood; D013237:Stereoisomerism
D004075:Diglycerides; D005989:Glycerides; D010712:Phosphatidic Acids; C044295:1,2-dioctanoylglycerol; D012701:Serotonin; D011493:Protein Kinase C