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Department of Pharmacology

Heidi E. Hamm, Ph.D.

Professor, Department of Pharmacology
Aileen M. Lange and Annie Mary Lyle Chair in Cardiovascular Research

Research Description

My work is focused on understanding the molecular basis of signaling mechanisms mediated by G proteins, which are switch proteins. G proteins are normally inactive, but a receptor that has received a specific signal can activate G proteins, leading to changes in the activity of enzymes that produce second messengers such as cyclic AMP and calcium.

The resulting changes in cellular activity underlie a large number of physiological processes. G protein-mediated signalling cascades are key regulators of many physiological processes, including processes of development, differentiation, and regulation of cell division. In the brain, many key neurotransmitters and neuromodulators mediate a myriad of functions by activation of such G protein cascades.

The research in my laboratory is aimed at understanding how G proteins become activated by receptors, how they in turn activate effector enzymes, and how they turn off. We determined the sites of interaction between proteins using a method of decomposing the proteins into small synthetic peptides and determining which peptides blocked interaction sites (Hamm et al., 1988; Rarick et al., 1992; Artemyev et al., 1993; Arshavsky et al., 1994). To understand the process more fully, we determined the atomic structure of the proteins in collaboration with the group of Paul Sigler. We used X-ray crystallography to solve the three-dimensional structures of G proteins in their inactive (GDP bound, (Lambright et al., 1994) and activated (GTPbgS-bound) forms (Noel et al., 1993). We caught a glimpse of the self-inactivating process in another crystal form, the transition state analog, Ga.GDP.AlF4- (Sondek et al., 1994). More recently, the structures of the bg subunit (Sondek et al., 1996) and the heterotrimeric G protein (Lambright et al., 1996) were solved. These high-resolution structural studies allowed us to postulate specific hypotheses regarding mechanisms of receptor:G protein interaction and activation, G protein subunit association-dissociation and effector activation.

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Vanderbilt Faculty Profile

Vanderbilt Brain Institute (VBI) 

Vanderbilt Center for Addiction Research (VCAR) 

Vanderbilt Institute of Chemical Biology (VICB)