Occurrence and functions of the phosphatidylinositol cycle in the myocardium.
In the last decade a great deal of attention was awarded to a signal transduction pathway which is utilized primarily by 'Ca2+ mobilizing' signal molecules and which involves the hydrolysis of a quantitatively minor phospholipid, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) by a PtdIns-specific phospholipase C (PLC). The evidence for the existence of receptor-mediated GTP binding protein-coupled PLC in myocardium and its possible functions are briefly summarized. The minireview is concentrated on the following aspects: 1) cellular localization and synthesis of polyphospho-PtdIns from PtdIns, 2) desensitization of the alpha 1-adrenergic agonist and endothelin-1 mediated PtdIns responses, 3) oscillatory Ca2+ transients initiated by PtdIns(4,5)P2 hydrolysis, 4) polyunsaturated fatty acids as constituents of polyphospho-PtdIns and of the protein kinase C activator 1,2-diacylglycerol (DAG), 5) source other than PtdIns(4,5)P2 contributing to the stimulated DAG, 6) role of the PtdIns pathway in cardiomyocyte growth and gene expression during the hypertrophic response.
Department of Biochemistry, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, The Netherlands.
J M
JM
Lamers
D H
DH
Dekkers
K
K
Bezstarosti
J T
JT
Meij
H A
HA
van Heugten
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002455:Cell Division; D004075:Diglycerides / Q000378:metabolism; D016232:Endothelins / Q000494:pharmacology; D004789:Enzyme Activation; D005227:Fatty Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008563:Membrane Lipids / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D015398:Signal Transduction
C011439:1,2-diacylglycerol; D000316:Adrenergic alpha-Agonists; D004075:Diglycerides; D016232:Endothelins; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D008563:Membrane Lipids; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D011493:Protein Kinase C; D002118:Calcium