National Doctoral Programme in
Informational and Structural Biology

Cell membranes are complicated two-dimensional assemblies of mobile interacting molecules. My laboratory uses biochemical and cell biological methods to study events at the membrane interface and lipid organization in systems ranging from model membranes to living cells. Lipids in cell and model membranes are not randomly distributed in a fluid bilayer but rather organize into laterally distinct dynamic regions with different packing densities. The tightly packed platforms in the cell plasma membrane, now generally known as lipids rafts, form a suitable environment for a large number of membrane proteins. A key feature of these rafts is their richness in glycolipids, sphingomyelin and cholesterol. Despite growing evidence connecting lipid rafts with multiple cellular events, their formation, maintenance and specific function still remain cryptic. A realistic view of the raft hypothesis could be described as a mixture of heavy and light cream that is on the verge of blending into a single fluid, but that is refreshed by new deliveries of one type of cream or the other [I]. This clearly describes the analytical and scientific tasks we are standing in front of when working with membranes. Therefor it is of utmost importance to use novel and specific tools that can address the underlying scientific problems, such as lipid transfer proteins.

Lipid transfer proteins are interesting candidates as highly targeted and specific lipid transporters, and sensors working in concert with the bulk lipid vesicular transport system and the membrane contact sites. Our central hypothesis is that the membrane environment produced by lipids, and the resulting changes in lateral organizational state of the lipids, regulate the lipid transfer protein activity.

1. Michael Edidin, Lipids on the frontier: a century of cell-membrane bilayers, Nature Reviews - Molecular Cell Biology 4 (2003) 414-418.