Kristy Luong

The lipid bilayer is extremely remarkable as transient temperature changes can alter the membrane phase. It has been proposed that membranes can exist in a liquid crystalline state and in a partially cholesterol-rich liquid-ordered phase. In the study of these membranes, regions that were found to be cholesterol-rich were also rich in sphingolipids and these areas are classified as detergent resistant membranes (DRM) as they remain intact after detergent treatment. Furthermore, it has been suggested that these sphingolipids and cholesterol molecules act as rafting devices allowing molecules involved in signal transduction pathways to congregate.

In addition, DRMs contain glycosylphosphatidylinositol (GPI) anchoring proteins, allowing protein linkage to the acyl chains of the lipids by two methods—either as a GPI anchor or through acylation with myristate or palmitate. The Src family, nonreceptor, protein tyrosine kinases are prime examples of the importance of acylation. It has been observed that T cells also contain DRM components and tyrosine phosphorylation has been found to be involved in the signaling pathway of the T cell receptor (TCR). According to previous studies conducted by Marano et al., there exists a correlation between the association of the TCR with DRMs for T cell activation to occur.

In this project, an anti-TCR antibody will be used to cause the aggregation process. A detergent will be added to break up most of the lipids in the membranes of Jurkat T cells and a sucrose gradient will be used to determine what associates with DRMs. Studies will first be conducted by labeling lipids with fluorescence and later the same process will be repeated with fluorescence antibodies for the labeling of proteins.