Physics Colloquium - Friday, Nov. 10th, 2006, 4:00 P.M.

E300 Math/Science Center; Refreshments at 3:30 P.M. in Room E200

Anne Kenworthy
Vanderbilt University

The search for lipid rafts: chasing a moving target

One of the most hotly debated areas in cell membrane biophysics is the structure and function of a class of membrane microdomains commonly referred to as lipid rafts. The lipid raft model invokes a critical role for cholesterol in generating liquid-ordered and liquid-disordered domains in membranes, which in turn are thought to organize proteins into functional complexes. The biological functions attributed to lipid rafts are many, including regulation of signal transduction, membrane trafficking, and pathogen entry and exit from cells. However, native lipid rafts have proven to be notoriously difficult to study, leading to the need for increasingly sophisticated approaches to probe their structure, composition, and dynamics in the context of living cells. I will discuss experiments from our laboratory which seek to pin down the nature of these domains, using a combination of experimental approaches sensitive to protein and lipid diffusion and inter-molecular distances in conjunction with mathematical modeling. Through these studies, we hope to gain a better understanding of the role lipid rafts play (or not) in regulating membrane architecture, protein and lipid dynamics, and cell membrane function.