Dr. Muallem's research at UT Southwestern involves the study of the function of Ca2+ transport and signaling proteins and their organization into complexes. Changes in cytoplasmic Ca2+ concentration serve to rapidly transmit information from the cell surface to the cell interior in order to initiate or regulate a variety of cellular functions. To achieve precise control of the messenger and effector roles of Ca2+, cells compartmentalize Ca2+ across cellular membranes to generate steep gradients that are discharged locally upon cell stimulation. Electrophysiological and confocal imaging techniques are used to monitor Ca2+ in subcellular compartments and follow the activity of Ca2+ pumps and Ca2+ channels. These approaches are complemented by a variety of biochemical and molecular techniques to study the organization of Ca2+ signaling complexes in microdomains of polarized cells.
Another aspect of his work is regulation of fluid and electrolyte secretion by epithelial cells. A key protein regulating epithelial function is the Cystic Fibrosis Transmembrane Regulator (CFTR). Dr. Muallem's work is geared towards understanding how CFTR regulates the activity of other transport proteins, in particular HCO3-transport across the luminal membrane. He believes that defective regulation of HCO3-transport is a critical problem in Cystic Fibrosis patients.
