Functional characterization of two single nucleotide polymorphisms of acyl-coenzyme A:cholesterol acyltransferase 2.
BACKGROUND
Acyl-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 (Glu(14)Gly, rs9658625) and 734C>T (Thr(254)Ile, 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.


METHODS
In 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.


RESULTS
Our results show that the enzymatic activity of mutant Glu(14)Gly 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.


CONCLUSIONS
These results suggest that the genetic variation at Glu(14)Gly is functionally important and may contribute to ACAT2 protein expression and stability.
Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore; Central Laboratory, Wuhan Children's Hospital, China. Electronic address: hexuelian2013@hotmail.com.
Xuelian
X
He
Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore.
Koon-Yeow
KY
Leow
Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Hongyuan
H
Yang
Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore. Electronic address: paehck@nus.edu.sg.
Chew-Kiat
CK
Heng
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D006801:Humans; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D002785:Sterol O-Acyltransferase / Q000737:chemistry / Q000235:genetics*; D000097587:Sterol O-Acyltransferase 2
D017931:DNA Primers; D002785:Sterol O-Acyltransferase; D000097587:Sterol O-Acyltransferase 2
Acyl-coenzyme A: cholesterol acyltransferase 2; Cholesteryl esters; Coronary artery atherosclerosis; Enzymatic activity; Functional characterization; Hypercholesterolemia