Inhibition of sterol transport protein function

Intracellular sterol transport proteins (STPs) are key regulators of cholesterol homeostasis and potential drug targets in a broad range of diseases including atherosclerosis, infectious diseases and cancer. Therefore, the ability to rapidly identify and validate small molecule inhibitors of these transporters is of great significance. In this chapter, we outline a series of biophysical and biochemical assays of increasing complexity to screen small molecules for inhibition of STPs in medium-to-high throughput. These include differential scanning fluorimetry to determine compound binding, competitive fluorescence polarization assays employing fluorescent sterols as tracers, and FRET-based lipid transport assays in synthetic liposomes. As these assays are now established for the majority of human STPs, compounds can also directly be profiled for selectivity across structurally and functionally related targets.