Student Talks
Alexis Nobleman
(Robinson Lab)
11:30am - 12:00pm
Impact of varying light levels on melanopsin mediated behaviors and signaling
My work centers on the visual pigment melanopsin, a seven transmembrane G-Protein Coupled Receptor (GPCR) that is activated by light and expressed in a subset of retinal ganglion cells. Unlike rod and cone opsins which primarily regulate image forming behaviors such as color and motion vision, melanopsin plays a predominant role in non-image forming behaviors including circadian photoentrainment and the pupillary light reflex. It was originally thought that melanopsin was only capable of signaling light information back to visual brain regions when exposed to an extremely bright stimulus. More recently however, it has been found that melanopsin actually signals over a wide range of light intensities, from very dim, scotopic, light to very bright, photopic light. I am currently working on understanding the molecular underpinnings of melanopsin’s ability to signal over this wide range of intensities, focusing on phosphorylation of the intracellular loops of the molecule that form the G-protein binding pocket.
Haya AlGrain
(Robinson Lab)
3:00pm - 3:30pm
Differential melanopsin signaling in mammals with unique retinal architecture
Mammals have evolved a wide variety of retinal architectures ranging from rod monochromats to trichromats such as humans who have diverse color vision. One commonality between all of these animals is their usage of ipRGCs, the third photoreceptor in the retina. Interestingly, animals with fewer types of cones tend to have a higher percentage of these photosensitive retinal ganglion cells. I study the differences between these animals at the protein level by assessing their species-specific melanopsin signaling, the opsin receptor responsible for ipRGC phototransduction. I am also the first to examine and categorize the presence of melanopsin in a diverse repertoire of animals from squirrels to killer whales.