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Ion channels are proteins that form aqueous pores in cell membranes. Because the lipid-rich membrane of the cell is impermeant to ions, ion channels are vital to the cell's ability to maintain and regulate the internal ionic composition of the cell. Ion channel pores have "binding sites" that are specific for the species of ion that is conducted - different kinds of channels selectively conduct Na, K, Ca, or Cl ions. Ion channels also have gates that open and close to control ion movement across the membrane. Channel gating can be controlled by various factors including membrane potential, chemicals and neuro-transmitters, mechanical stretch, and heat. For example, the heart beat is controlled by at least a dozen different kinds of ion channels. Cardiac contraction is initiated when a calcium channel opens, permitting Ca to flow into the heart cell. Other channels in the heart control when the Ca channels open and how long they remain open. Secretion of fluids into the gut, airway, and reproductive tract are also controlled by ion channels. Our lab has been interested in understanding the roles various kinds of ion channels play in cell physiology.

Presently, our main interest is devoted to chloride channels. Chloride channels are essential for fluid and salt secretion from epithelia, play a role in sensory transduction, regulate both cytosolic pH and the pH of intracellular organelles, control neuronal and cardiac excitability, and contribute to bone resorption by osteoclasts. Defects in chloride channels produce a wide variety of diseases including cystic fibrosis, myotonias, osteopetrosis, deafness, kidney disorders, and neurodegenerative diseases. We are focusing on the role chloride channels play in the retina and trying to understand how chloride channel dysfunction produces macular degeneration, which is a leading cause of blindness