出版社:American Society for Biochemistry and Molecular Biology
摘要:Triglyceride synthesis in most mammalian tissues involves thesequential addition of fatty acids to a glycerol backbone, withunique enzymes required to catalyze each acylation step. Acylationat the sn-2 position requires 1-acylglycerol-3-phosphate O-acyltransferase(AGPAT) activity. To date, seven Agpat genes have been identifiedbased on activity and/or sequence similarity, but their physiologicalfunctions have not been well established. We have generateda mouse model deficient in AGPAT6, which is normally expressedat high levels in brown adipose tissue (BAT), white adiposetissue (WAT), and liver. Agpat6-deficient mice exhibit a 25%reduction in body weight and resistance to both diet-inducedand genetically induced obesity. The reduced body weight isassociated with increased energy expenditure, reduced triglycerideaccumulation in BAT and WAT, reduced white adipocyte size, andlack of adipose tissue in the subdermal region. In addition,the fatty acid composition of triacylglycerol, diacylglycerol,and phospholipid is altered, with proportionally greater polyunsaturatedfatty acids at the expense of monounsaturated fatty acids. Thus,Agpat6 plays a unique role in determining triglyceride contentand composition in adipose tissue and liver that cannot be compensatedby other members of the Agpat family.Supplementary key words acyltransferase • gene-trap • adipose tissue • energy expenditure • 1-acylglycerol-3-phosphate O-acyltransferase
Abbreviations: AGPAT, 1-acylglycerol-3-phosphate O-acyltransferase; BAT, brown adipose tissue; DAG, diacylglycerol; DGAT1, acyl-coenzyme A:diacylglycerol acyltransferase-1; GPAT, glycerol-3-phosphate acyltransferase; HF/HC, high-fat/high-carbohydrate; TAG, triacylglycerol; WAT, white adipose tissue