The cholesterol content of animal cells is carefully regulated.  This regulation applies not only to the overall cholesterol level in the cell, but also to the concentration of cholesterol in the membrane of each organelle.  For instance, cholesterol constitutes almost half of the lipids of the plasma membrane but less than ten percent of the lipids of the endoplasmic reticulum. Maintaining the proper level and distribution of cholesterol (which is virtually insoluble) must require an efficient transport network involving many proteins, the details of which are largely unknown.  We are interested in understanding the mechanisms by which transport proteins can move lipids such as cholesterol between and across membranes.  We use all modern tools of biochemistry and cell biology, as necessary, to attack these problems. 

In addition, we have a long-standing interest in how cholesterol modulates the physical properties of model membranes and the activity of reconstituted membrane proteins.