Date of Award

12-1-1997

Degree Type

Restricted Access Thesis

Degree Name

Master of Science

Field of Study

Pharmacology and Neuroscience

Department

Graduate School of Biomedical Sciences

First Advisor

Eugene E. Quist

Second Advisor

Thomas Yorio

Third Advisor

Ming-Chi Wu

Abstract

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.

Comments

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. W 4.5 W2455R 1997

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