Functional characterization of two single nucleotide polymorphisms of acyl-coenzyme A:cholesterol acyltransferase 2

• We characterized the functional impact of two non-synonymous SNPs of ACAT2.
• Nucleotide sequences in the Glu14Gly region are entirely conserved.
• The Gly14 variant showed higher expression level of the ACAT2 protein.
• The Gly14 variant may contribute to susceptibility of hypercholesterolemia and CAD.

BackgroundAcyl-coenzyme A:cholesterol acyltransferase 2 (ACAT2) plays a critical role in the formation of cholesteryl esters from cholesterol and fatty acids, and is a potential target for treating hypercholesterolemia. We recently reported the significant effects of two human ACAT2 gene polymorphisms, 41A>G (Glu14Gly, rs9658625) and 734C>T (Thr254Ile, rs2272296), on plasma lipid levels and coronary artery disease susceptibility in a case–control association study. In the present study, we evaluated the possible biological influence of the two polymorphism using two approaches.MethodsIn the first approach, the functional impact of the two polymorphisms was predicted in-silico using available web-based software, and in the second approach, the varying functions of the two polymorphisms were characterized in in vitro experiments, using ACAT2-deficient AC-29 cells.ResultsOur results show that the enzymatic activity of mutant Glu14Gly is approximately two times higher than wildtype, and that this increase is primarily due to the increased expression and/or stability of the mutant ACAT2 protein.ConclusionsThese results suggest that the genetic variation at Glu14Gly is functionally important and may contribute to ACAT2 protein expression and stability.