Distinguished Speaker Series | Nikolai Artemyev, PhD

Heterotrimeric GTP-binding proteins (G-proteins) are used by cells to transduce signals from the extracellular environment through surface receptors to intracellular effector proteins. One of the best model systems for studying mechanisms of G protein signaling is the rod photoreceptor visual transduction cascade. Our laboratory focuses on investigation of specific protein-protein interactions between the photoreceptor – rhodopsin, the rod G protein - transducin, and the effector enzyme - cGMP-phosphodiesterase. We study the modulation of transducin by retinal regulators of G protein signaling (RGS) and other accessory proteins. To understand the activation and turn-off mechanisms of transducin and cGMP-phosphodiesterase upon transduction of a visual signal we employ tools and techniques such as transgenic animal models, site-directed mutagenesis, synthetic peptides, site specific antibodies, cross-linking, and fluorescence spectroscopy. The high levels of sequence homology between different types of G proteins, as well as the structural similarities observed in their crystal structures suggest that numerous G protein signaling systems have similar mechanisms of activation. Our ultimate goal is to understand the mechanisms of regulation of G protein signaling at the molecular level.