-----------------------------------------------------------

Fluid Dynamics Seminar

Monday, Aug 28, 2006, 2:30 PM
Cullimore Lecture Hall, Room 611
New Jersey Institute of Technology

"Lipid raft" formation: Experiments and mathematical modelling

Linda Cumming

School of Mathematical Sciences, Division of Applied Mathematics, University of Nottingham

Abstract

Living cells have an outer membrane made of lipid molecules, arranged in a bilayer. These bilayers are inhomogeneous in composition, containing so-called "lipid rafts" that are enriched in cholesterol and sphingomyelin. Rafts are believed to recruit certain proteins, and thus to be very important for proper cell function. Moreover, rafts are implicated in the mechanism of virus entry into cells, and in many cell-signalling processes, and so are the focus of much current research activity. Since real cells are difficult to probe and enormously complicated, raft formation and disassembly may be studied in model lipid bilayers. We study the simplest model system of a bilayer composed of cholesterol and phosphatidylcholine (PC). The formation of cholesterol-enriched regions (the "rafts") is monitored using fluorescence microscopy. We propose a mathematical model for the raft formation, based on considerations of the interactions and bond formations between individual cholesterol molecules. Results of the mathematical model are compared to the experimental system, and good agreement is found. We discuss the implications of our findings, and directions for future work.