CPM Seminar

“Really Good” Cholesterol's Role in Membrane Organization

Jenifer Thewalt

Departments of Molecular Biology & Biochemistry and Physics
Simon Fraser University

The plasma membrane surrounding a typical mammalian cell has a lipid bilayer core structure only a few nanometers thick. This membrane governs important cell processes such as the transmission of information and chemicals into or out of the cell via specialized membrane proteins. The lateral organization of lipids is thought to be a crucial mechanism for controlling the location and function of these proteins.

Cholesterol is one of the major components of plasma membranes and dramatically affects other lipids, however many aspects of lipid membranes containing cholesterol remain poorly understood. For example, it is postulated that membranes contain distinct cholesterol-rich regions but these are difficult to measure in living cells. “Model” membranes of defined lipid composition are thus used to evaluate lipid interactions. Deuterium NMR is especially useful for measuring lipid dynamic structure and liquid-crystalline phase behaviour, and the results provide insight into cholesterol's role in cell membrane organization.