Regulation and Characterization of Cardiac Phosphoinositide-Specific Phospholipase C (PLC) Isoenzymes
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Wang, Juan, Regulation and Characterization of Cardiac Phosphoinositide-Specific Phospholipase C Isoenzymes. Master of Biomedical Science, Dec., 1997, 79 pp., 20 illustration, bibliography, 62 titles. It is hypothesized that myocardial phosphoinositide-specific phospholipase C (PLC) isoenzymes are regulated by physiological intracellular Ca2+ and by cytosol-membrane translocation. The regulation and identification of PLC isoenzymes in rat and dog ventricular subcellular fractions were studied. PLC-β1, PLC-β3 and PLC-δ1 were identified in rat and dog cytosol and microsomal membranes by chromatographic separation, enzyme assays and western blotting. Truncated PLC-β isoforms with molecular weights of 69 kDa and 114 kDa were isolated from rat and dog cytosol, respectively. Species differences in the relative distribution of PLC isoenzymes were evident as PLC-δ dominant in rat whereas PLC-β isoenzymes were dominant in dog. A 91 kDa cytosolic protein which did not contain PLC activity alone markedly led to PLC activation when combined with microsomes. The activator protein was immunoprecipitated with an anti-PLC-δ identifying this activator as an inactive PLC-δ isoenzyme. These studies indicate that cytosolic PLC-δ may be activated by translocating to membranes. In addition, proteolysis may be involved in long term activation of cytosolic PLC isoenzymes. Further studies will be required to resolve the physiological significance of these modes of cardiac PLC activation.
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Cell and Developmental Biology
Cell Biology
Cells
Cellular and Molecular Physiology
Circulatory and Respiratory Physiology
Comparative and Laboratory Animal Medicine
Immunity
Immunology and Infectious Disease
Life Sciences
Medical Cell Biology
Medical Sciences
Medicine and Health Sciences
Other Cell and Developmental Biology
Other Immunology and Infectious Disease
Physiology
Systems and Integrative Physiology
Regulation
characterization
cardiac phophoinositide-specific phospholipase C isoenzymes
PLC
intracellular calcium
Ca2+
isoenzymes
rats
dogs
cytosolic protein
cytosolic PLC-δ