Cholesterol transport via ABCA1: New insights from solid-phase binding assay

► We investigated ABCA1 molecular function by tagging and isolating the protein. ► The 1D4 tag did not modify the protein expression/localization within the cells. ► The 1D4 tag did not impair ABCA1-dependent cholesterol efflux to apo A-I. ► Solid-phase binding assays showed no direct binding of cholesterol to ABCA1. ► Solid-phase binding assays showed no direct binding of apo A-I to ABCA1 either.