Indu Ambudkar, Ph.D., Chief
Mission
Studies in the Secretory Physiology Section (SPS) are primarily directed towards understanding the mechanisms by which a neurotransmitter signals a functional secretory response in salivary epithelial cells. Our previous studies have provided understanding of the molecular components involved in neurotransmitter-stimulated Ca2+ signaling in these cells. Recently, our efforts have been focused on the Ca2+ influx pathway in salivary gland cells, which has been suggested to be critical for the secretory function of the gland. Ca2+ influx in salivary gland cells occurs via the poorly understood "store-operated Ca2+ entry channel." Our previous studies have provided considerable understanding regarding properties of this Ca2+ entry mechanism. Our recent studies have been directed towards identification of (i) the molecular components, and (ii) the gating mechanism of the store-operated Ca2+ entry channel. Our studies utilize a variety of approaches, including electrophysiology, microfluorimetry, molecular biology, as well as biochemistry to determine the molecular basis of Ca2+ entry in salivary gland acini and the role of Ca2+ entry in fluid secretion. Our recent and ongoing studies are directed towards identifying the function, regulation, trafficking and assembly of newly identified TRP family of ion channels proteins. Most recently, we have proposed that TRPC1 is a component of the Ca2+ influx channel in salivary gland acinar cells and is critically involved in regulation of saliva secretion. Another member of this superfamily TRPV4 has a critical role in volume regulation of salivary gland acini and directly related to water channel (AQP5) function. Thus, TRP channels are potential targets for therapy of salivary gland dysfunction induced by irradiation of Sjogren’s Syndrome.