Stimulation of inositol phospholipid hydrolysis is the initial intracellular response to transmembrane receptor activation by a wide array of extracellular chemical signaling messengers. Inositol phospholipid hydrolysis is stimulated by most extracellular signaling molecules through G protein subunits which activate phospholipase C-beta (PLC-beta) enzymes. Further regulation (e.g. inhibition) of inositol phospholipid hydrolysis may be mediated by alternative factors including covalent modification and proximity to membrane bound substrate. This project's long-term goal is an accurate, rigorous description of PLC-beta3 isoenzyme regulation by kinases, lipid binding domains, and non-G protein intermolecular interactions. The kinetics of phosphorylation-mediated inhibition of PLC-beta3 hydrolytic activity will be quantitated in well-controlled in vitro assays. Phospholipid and membrane binding affinities of putative lipid binding domains within the PLC-beta3 molecule will be assessed to further associate structure with function and regulation of PLC- beta activity. Additionally, the association of PLC-beta3 with putative interacting proteins, other than G proteins or kinases, will be identified and the function of these intermolecular interactions quantitated both in vivo and in vitro. These studies, which aim to detail at a molecular level multiple means of regulation of PLC-beta3 activity beyond the well-characterized G protein activation pathway, will contribute to a greater understanding of the basic mechanisms of signal transduction. A detailed, functional map of PLC-beta enzyme regulation may contribute to the design of novel therapeutic agents that intervene selectively into pathophysiological PLC-beta-mediated processes; hormone and neurotransmitter responses associated with PLC-beta activation include, among many others, smooth muscle contraction, platelet aggregation, hormone secretion, smooth muscle hypertrophy and hyperplasia, neuronal activation, and malignant cell proliferation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM061244-02
Application #
6526096
Study Section
Pharmacology A Study Section (PHRA)
Program Officer
Cole, Alison E
Project Start
2001-08-01
Project End
2006-07-31
Budget Start
2002-08-01
Budget End
2003-07-31
Support Year
2
Fiscal Year
2002
Total Cost
$214,261
Indirect Cost
Name
Oregon State University
Department
Type
Schools of Pharmacy
DUNS #
053599908
City
Corvallis
State
OR
Country
United States
Zip Code
97339
Zhang, Yong; Kwon, Sun Hyung; Vogel, Walter K et al. (2009) PI(3,4,5)P3 potentiates phospholipase C-beta activity. J Recept Signal Transduct Res 29:52-62
McCullar, Jennifer S; Malencik, Dean A; Vogel, Walter K et al. (2007) Calmodulin potentiates G beta gamma activation of phospholipase C-beta3. Biochem Pharmacol 73:270-8
Zhang, Yong; Vogel, Walter K; McCullar, Jennifer S et al. (2006) Phospholipase C-beta3 and -beta1 form homodimers, but not heterodimers, through catalytic and carboxyl-terminal domains. Mol Pharmacol 70:860-8
Filtz, Theresa M; Niibori, Yoshiko (2004) Desensitization of angiotensin-stimulated inositol phosphate accumulation in human vascular smooth muscle cells. Eur J Pharmacol 502:11-9
McCullar, Jennifer S; Larsen, Shana A; Millimaki, Ryan A et al. (2003) Calmodulin is a phospholipase C-beta interacting protein. J Biol Chem 278:33708-13