Several areas of research related to cell signaling are being investigated in Dr. Stephen Soltoff's laboratory. One long-standing project concerns the activation of parotid acinar epithelial cells by neurotransmitter agonists. The parotid gland, one of the three major salivary glands, secretes a primary fluid of electrolytes and proteins which, after modification by the ductal system, make up saliva. The initial signal transduction events and the activation of specific ion transport systems involved in stimulation of acinar cells by neurotransmitter agonists are a major focus of investigation. Recent studies in Dr. Soltoff's lab have indicated that protein kinase C (PKC) and tyrosine phosphorylation play a role in mediating early signal transduction events. One member of the PKC family of proteins, PKCdelta, becomes tyrosine phosphorylated in response to stimuli that promote fluid secretion. Current studies are examining the effects of this tyrosine phosphorylation on PKCdelta activity and the physiological role of this and other PKCs in a variety of cells.
Additional studies focus on the signaling mechanisms and cellular effects initiated by the activation of various types of P2 purinergic receptors in cells. Many cells are activated by extracellular nucleotides, which can be released from nerves or non-neural cells as a paracrine or autocrine signal. P2Y receptors are seven transmembrane G-protein coupled receptors, while P2X receptors are cation channels. Both subtypes are linked to various effector molecules that promote numerous biochemical signals related to growth, differentiation, and other functions.