This special Physics department colloquium is scheduled for Wednesday 11/30/16 at 2:00 PM in the Kenwood Interdisciplinary Research Complex (KIRC) Room KEN 2035. Anyone is welcome.

Investigation of Membrane Receptors’ Oligomers Using Fluorescence Resonance Energy Transfer and Multiphoton Microscopy in Living Cells
Ashish Mishra, PhD Candidate/UWM Dept. of Physics

Investigating quaternary structure (oligomerization) of macromolecules (such as proteins and nucleic acids) in living systems (in vivo) has been a great challenge in biophysics, due to molecular diffusion, fluctuations in several biochemical parameters such as pH, quenching of fluorescence by oxygen (when fluorescence methods are used), etc.

We studied oligomerization of membrane receptors in living cells by means of Fluorescence (Förster) Resonance Energy Transfer (FRET) using fluorescent markers and two photon excitation fluorescence micro-spectroscopy. Using suitable FRET models, we are able to determine the stoichiometry and quaternary structure of various macromolecular complexes. In this talk, I will present results of the above-mentioned study for two membrane receptors: (1) sigma-1 receptor and (2) rhodopsin, described below:

1) Sigma-1 receptors are molecular chaperone proteins, which also regulate ion channels. S1R seems to be involved in substance abuse, as well as several diseases such as Alzheimer’s.

2) Rhodopsin is a prototypical G protein coupled receptor (GPCR) and is directly involved in vision. GPCRs form a large family of receptors that participate in cell signaling by responding to external stimuli such as drugs, thus being a major drug target (more than 40% drugs target GPCRs).