The vast majority of signaling pathways in mammalian cells are mediated by G proteins and their receptors, GPCRs. GPCR signaling has been studied mostly using vitro approaches. To observe the activity and localization of signaling proteins at the subcellular level in real time we use wide field and confocal microscopy to image sensors made up of these proteins tagged with fluorescent proteins. We use FRET, FRAP, FLIP and a photoswitchable protein, Dronpa. We also use microfluidic channels to examine spatial localization of signaling. We have recently shown that G protein subunits translocate reversibly from the plasma membrane to intracellular organelles in response to receptor stimulation. The translocation suggests that the function of activated G proteins is not restricted to the plasma membrane as thought. Finally, we are interested in developing sensors that will be of value in non-invasively and rapidly screening for drugs targeted at GPCRs which are among the most important targets for therapeutic drugs.
Research Publications
Akgoz M, Kalyanaraman V, Gautam N. G protein betagamma complex translocation from plasma membrane to Golgi complex is mediated by receptor gamma subunit interaction. Cell Signal 2006 18:1758-1768.
Azpiazu I, Akgoz M, Kalyanaraman V, Gautam N. G protein betagamma11 complex translocation is induced by Gi, Gq and Gs coupling receptors and is regulated by the alpha subunit type. Cell Signal 2006 18:1190-1200.
Akgoz M, Kalyanaraman V, Gautam N. Receptor mediated reversible translocation of the G protein betagamma complex from the plasma membrane to the Golgi complex. J Biol Chem 2004 279:51541-51544.
Azpiazu I, Gautam N. A FRET based sensor indicates that receptor access to a G protein is unrestricted in a living mammalian cell. J Biol Chem 2004 279:27709-27718.
Gautam N. A Conformational Switch Regulates Receptor-G protein Interaction. Structure 2003; 11:359-60. Review
Contact Info
N. Gautam, Ph.D.
Office Location: 5548 Clinical Sciences Research Bldg.
Office Phone: 314-362-8568
Campus Box: 8054
Fax: 314-362-8571
gautam@morpheus.wustl.edu
http://elysium.wustl.edu/nglab/
