Advances in understanding of the role of lecithin cholesterol acyltransferase (LCAT) in cholesterol transport.

We review the structure and function of lecithin cholesterol acyl transferase (LCAT), the advances in the studies of molecular genetics of LCAT and its deficiency states as well as the developments in assessment of LCAT activity particularly the concept of measurement of fractional esterification rate of plasma cholesterol in the absence of apoB lipoproteins (FER(HDL)) as an indication of atherogenic risk. We discuss LCAT reaction from two points of view: one that is consistent with the general belief in LCAT antiatherogenic potential and another, namely, a proposed concept of potentially opposing roles of LCAT in normal and dyslipidemic plasmas. While other plasma lipoproteins can (in addition to HDL) provide unesterified cholesterol (UC) for LCAT reaction, HDL may play an unique role in trafficking of newly formed cholesteryl esters (CE) rather than as a primary acceptor of cellular cholesterol. Thus, the plasma HDL, specifically the larger (HDL2b) particles, direct the efflux of most of (LCAT produced) CE to its specific catabolic sites rather than to potentially atherogenic VLDLs and back to LDLs.