This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Nerve impulses and muscle contraction are triggered by an electrical impulse called an action potential. Proteins known as voltage gated ion channels allow ions to move across cell membranes, causing a change in the electrical potential between the two sides of the membrane, which is then propagated along the membrane as the electrical impulse. In all biological systems, the only ions known to mediate action potentials are sodium (Na+), calcium (Ca2+) and chloride (Cl-). This project addresses the mechanism underlying the bioluminescence of dinoflagellates (single celled aquatic organisms), some of which emit flashes of light. By making electrical recordings in dinoflagellate membranes this project will test the hypothesis that protons (H+) mediate the action potential that sparks this light emission. The discovery that proton channels trigger bioluminescence in this way would be unprecedented. The gene that codes the protein that forms the proton channel in dinoflagellates will be identified, permitting the study of the structural properties of the channel and providing an understanding of how it performs its key functions. This project opens several completely new areas, including proton channels as conductors of action potentials; electrophysiological measurements of dinoflagellate membranes; and identification of an ion channel gene in dinoflagellates. This study will expand the range of life forms known to express voltage gated proton channels, and the discovery of novel functions in dinoflagellate proton channels could shed new light on their actions in vertebrates.
Broader impact. This project will expose undergraduate students and a postdoctoral fellow to a unique interdisciplinary investigation, involving dinoflagellate biology and bioluminescence, the electrophysiology and biochemistry of proton channels, and bioinformatics and structural biology. The studies to be undertaken range from field work (collecting dinoflagellates in the Gulf of Mexico) to electrophysiological measurements and molecular biological experiments in the laboratory. The students and postdoctoral fellow will be given the opportunity to author publications and to present their work at scientific conferences.
