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Name:	John R. Hepler
Position:	Professor of Pharmacology
Degree:	Ph.D., University of North Carolina, 1988
Programs:	MSP, Full Member BCDB, Full Member NS, Full Member
Phone:	404 727-3641
Address:	G205 Rollins Research Center, 1510 Clifton Rd, 1940/001/1AF
Email:	jhepler@emory.edu
Website:	http://www.pharm.emory.edu/jhepler/
Research Descriptions:
Short:	Cellular roles and regulation of novel signaling proteins/pathways used by neurotransmitters.
Long:	My general interests center on understanding how cells receive and process information from their surroundings. My specific research interests focus on understanding the biochemical properties and cellular functions of G proteins, their signaling pathways, and how these are regulated by the cell. The binding of hormones and neurotransmitters at specific receptors on the cell surface represents only the first step in a cascade of molecular events that underlies transmembrane signaling. Stimulation of these receptors results in activation of effector proteins (e.g., enzymes and ion channels) which mobilize chemical second messengers (e.g., cAMP, Ins(1,4,5)P3, Ca++, diacylglycerol) that, in turn, initiate characteristic cellular responses. In all eukaryotic organisms, a family of 21 distinct mammalian GTP-binding and hydrolyzing proteins (G proteins), plays an essential role in linking a vast number of cell surface receptors to regulation of effector protein activity. We combine techniques in molecular biology (e.g., RNA, DNA manipulation), intact cell biology and tissue culture, recombinant protein expression and purification, and protein chemistry to study G protein functions. Current projects include: 1) Defining functional correlates for biochemical differences found among the G proteins that regulate phospholipase Cb and inositol lipid signaling (Gq, G11, G14 and G16), and 2) Cellular roles and biochemical properties of RGS proteins (Regulators of G protein signaling), a novel family of more than 20 distinct mammalian proteins that directly regulate G protein functions. G protein coupled receptors and their associated signaling proteins are central players in the regulation of cell and organ physiology and serve as primary targets for therapeutic intervention in human disease. Our studies of these proteins and how they are regulated will provide a better understanding of the roles these signaling molecules play in physiology and disease.