Detecting Ligands Interacting with Lipoprotein Lipase

The primary role for lipoprotein lipase (LPL) is hydrolysis of triglycerides in chylomicrons and very low density lipoproteins (VLDL). This enzyme has also been implicated in the process of atherogenesis (for reviews see refs. 1 and 2 ). Additional enzymatic activities of LPL include retinyl ester hydrolysis and fatty acid ethyl ester synthesis (3 ,4 ). Recent studies from several laboratories suggest that LPL may have roles unrelated to its enzymatic activity. For example, LPL increases lipoprotein binding to matrix and lipoprotein binding and uptake by cells, a function that does not appear to require catalytic activity. Since LPL has domains that interact with lipid, apoB, and cell surface molecules, it has been suggested that LPL forms a bridge between lipoproteins and cell surfaces (see refs. in 2 ). This bridging function has been postulated to play a role in the accumulation of lipoproteins by cells in vivo.