Kathleen A. Hoffman

Phototransduction in the Vertebrate Visual System

As part of the Mathematical Biology undergraduate training grant UBM at UMBC, Prof. P. Robinson (Biology Department, UMBC) and I are mentoring four undergraduate students Drew Thatcher, Kevin Herold, Abigail Jackson , Jessica Ortega on modeling phototransduction in the vertebrate visual system. Previous students J. Meisel and Kim Daniels that worked on this project are in graduate school at U. Penn and Harvard, respectively. Building on modeling work on rhodopsin, a vertebrate opsin that has been previously studied and modeled, we focus our research on melanopsin, a unique vertebrate opsin discovered just ten years ago in light sensitive ganglion cells in the vertebrate visual system. The goal of our joint research project is to model the deactivation of the phototransduction cascade that converts a photon of light to an electrical signal that gets transmitted to the brain, via a chemical cascade. Based on recent experimental results from the Robinson lab, the deactivation of this chemical cascade accelerates in the presence of over expressed beta-arrestin. We have developed a mathematical model of this process that predicts this response. We used experimental data of wild-type melanopsin to fit model parameters and the resulting model successfully predicts experimental results where beta-arrestin is over-expressed.

Maintained by: Kathleen A. Hoffman (khoffman@math.umbc.edu).