Critical physiological events throughout the body are controlled by extracellular signals from neurotransmitters and hormones acting on cell surface receptors. Receptors transduce these signals to alter intracellular metabolism and cellular responsiveness through heterotrimeric G protein/second messenger pathways or through small GTP-binding protein/protein kinase cascades.
The mechanisms that control the responsiveness of target organ G protein-coupled receptors include receptor phosphorylation and desensitization by G protein-coupled receptor kinases (GRKs). We have created mice lacking each of the three members of the GRK4 subfamily of GRKs (GRK4, GRK5 and GRK6), and are examining the functional effects of this loss of function on the physiology of receptors controlling gastrointestinal, heart, lung, immune and brain functions.
An important open question in the study of cellular regulation is understanding how cells coordinate the activity of multiple receptor pathways into a coherent cellular response. Our recent discovery that large multidomain ARF GTPase-activating proteins (GAPs) of the GIT family can serve as oligomeric scaffolding proteins for numerous signaling molecules and help coordinate heterotrimeric G protein and multiple small GTP-binding protein pathways, suggests that other multidomain ARF GAPs may also function in analogous manner as coordination centers. We are examining the functional roles of GIT proteins and related ARF GAPs in crosstalk among cellular signaling pathways, with particular emphasis on gastrointestinal and behavioral roles using GIT1 and GIT2 knockout mice.
Education and Training
- Ph.D., City University of New York, 1992