Mathematical Biology Seminar David Krizaj, Opthalmology, University of Utah, Caltech Wednesday Feb. 25, 2008 3:05pm in LCB 215 "Spatial and temporal regulation of intracellular calcium in photoreceptors" Abstract: The calcium ion plays a central role in photoreceptor function: it controls both photoreceptor input (represented by the phototransduction cascade) and its output (represented by the rate of neurotransmitter release); it has numerous other tasks as well, including regulation of gene expression and cytoskeletal dynamics. It is obvious that the ability of calcium to do its work in rods and cones depends on positioning of its influx, clearance and sequestration mechanisms represented by assorted channels and pumps. My presentation has two aims. First, I will show how we characterized some of the important players in calcium regulation in rod and cone photoreceptors. This will include a demonstration of the methods we use in the lab, from Ca imaging, field potential recordings and patch clamp to PCR, immunolocalization and RNAi. In the second part I will discuss the issues that, in my mind, are still unresolved with respect to Ca signaling in photoreceptors. I will try to emphasize questions that could benefit from biophysical analysis such as the relationship between local and global Ca signaling, diffusion and buffering.