Spherical HDL particles bound to the cell-surface SR-BI receptor are disassembled, with the release of pre-beta HDL (essentially apoA-I lipoprotein with a few molecules of bound lipid) and the cellular uptake of the bulk of the HDL-associated cholesterol, cholesterol esters, phospholipids, and triacylglycerols. The specificity and efficiency of this process has been demonstrated through a variety of studies in tissue culture model systems (Rigotti et al. 2003; Silver and Tall 2001). The process is annotated here as a concerted event occuring at the cell surface but its molecular details remain incompletely defined and it is possible that the HDL particle is internalized while undergoing disassembly.