Molecular Mechanisms of Light-Signaling in a Novel Lineage of Ciliated Photoreceptors

Marine Biological Laboratory, Woods Hole MA

Investigators

Abstract

Vision is the best understood sensory modality by which organisms gain information about their surroundings. In addition, it has also served as a particularly fruitful model system for studying, in a broader context, how cells react to external stimuli, because similar underlying chemical and electrical phenomena occur in a host of other biological functions. The long-term objectives of this project are to elucidate the mechanisms that enable different visual cells to convert impinging light stimulation into electrical signals, and to regulate their own responsiveness in such a way that they can function over an extraordinarily wide range of ambient illumination. These experiments will focus on a novel lineage of light-sensing cells, whose machinery appears to be relevant for sensory processing across the evolutionary spectrum, from unicellular organisms to man. The investigators will build on an extensive body of information, garnered primarily in their own laboratory, to characterize a novel enzyme that is activated upon light absorption, and the mechanisms by which it conveys its message to another protein on the cell surface, which shuttles electrically charged molecules across the cell membrane, thus initiating an electrical signal for the brain to process. The experimental approach is highly multi-disciplinary, making use of electrical and optical methods to monitor cell function, as well as cell- and molecular-biological tools to identify, localize and manipulate key signaling molecules. Because of the diversity of approaches and the generality of the problem - which bring together disciplines such as cell physiology, sensory information processing, and biochemical signaling - this project provides unusually rich opportunities for training graduate students; the fact that an explicit effort will be made to recruit from pools of candidates less frequently exposed to such scientific opportunities enhances the educational impact that this research will have.