Alexander Starushchenko, Ph.D., Assistant Professor, Physiology
Education:St. Petersburg University, St. Petersburg, Russia, B.S.,St. Petersburg University, St. Petersburg, Russia, M.S., Institute of Cytology RAS, St. Petersburg, Russia, Ph.D.
Link to Physiology
We are interested in the normal and pathophysiological regulation of epithelial ion channels. A particular emphasis is placed on the epithelial Na+ channel (ENaC). This channel, found in the kidney, controls plasma sodium and volume levels and thus, sets blood pressure. Gain of function mutations in ENaC and the aldosterone signaling cascade lead to hypertension associated with inappropriate sodium conservation and volume expansion. Also abnormal ENaC activity has been associated with altered sodium transport and cyst formation in autosomal recessive form of PKD. We use a number of contemporary methodologies, including electrophysiology, molecular biology, biochemistry, and fluorescence microscopy to investigate regulation of ENaC and aldosterone signaling. We routinely use reconstituted channels in mammalian expression systems, immortalized epithelial cell lines and freshly isolated rat collecting ducts in this regard. We perform real-time measurement of ion channel activity and fluorescence imaging, and perform biophysical analysis of ion channel activity and gating, create point mutations and chimeric proteins and genes, investigate cellular signal transduction, and study channels in heterologous expression systems as well as in native principal cells. Currently we are working on projects including: 1) to determine the effects of small G proteins on ENaC activity and assign the cellular mechanism(s) of small G protein regulation of ENaC, 2) to identify the small G proteins responsible for trafficking of ENaC, 3) to identify cytoskeletal targets of small G proteins relevant to ENaC trafficking and their mechanism of action on the channel, 4) to determine which domains within ENaC subunits are necessary and modulatory for channel function, and 5) to identify which sequence tracts/domains within ENaC subunits are functional equivalent and which provide unique properties to the channel.