Speaker: Christopher V Kelly
Associate Professor
Department of Physics and Astronomy
Wayne State University

Title: Nanoscale membrane curvature, lipid phases, molecular sorting, and single-molecule diffusion

Abstract: Cellular homeostasis requires the precise spatial and temporal control of membrane shape and composition. However, the nanoscopic interdependence of membrane properties is difficult to observe and poorly understood. We developed and employed model samples, fluorescence microscopy methods, and computational simulations to observe single-molecule behavior with varying membrane composition, phase, temperature, and shape. For example, engineered, hemispherical membrane buds induced lateral compositional heterogeneity in otherwise homogeneous membranes. The curvature-induced sorting of lipid phases was quantified by the sorting of disorder-preferring fluorescent lipids, single-lipid diffusion measurements, and simulations that couple the lipid phase separation to the membrane shape. Unlike single-component membranes, lipids in phase-separated membranes demonstrated faster diffusion on curved membranes than the surrounding, flat membrane. These results support the hypothesis that the coupling of lipid phases and membrane shape couple to yield lateral membrane composition heterogeneities with functional consequences.

Biography:

Dr. Christopher V. Kelly joined the Department of Physics and Astronomy at Wayne State University in 2013. Prior to moving to Detroit, Michigan, Dr. Kelly was a postdoctoral fellow at Cornell University with a Kirschstein-NRSA NIH postdoctoral fellowship. Dr. Kelly earned his B.A. from Oberlin College in Physics, his M.S.E. in Electrical Engineering from the University of Michigan, and his Ph.D. in Applied Physics from the University of Michigan. Dr. Kelly is finishing his NSF CAREER Award focused on curvature in membrane bilayers and beginning his R01 grant from the NIDDK focused on the biophysics of membrane monolayers surrounding lipid droplets. He is the director of the Richard Barber Interdisciplinary Research Program, which provides research opportunities to undergraduate students across WSU in interdepartmental research projects. His expertise includes nanoscopic optics, nanoengineering, and computational techniques to resolve the underlying biophysical principles that govern biological membranes.