ACAT2 Recombinant Rabbit mAb

ACAT2 (acyl-CoA:cholesterol acyltransferase 2) is a membrane-bound enzyme predominantly expressed in hepatocytes and intestinal mucosal cells. Unlike the broadly expressed ACAT1 isoenzyme, its function exhibits pronounced tissue specificity. The enzyme consists of 526 amino acids with a molecular weight of approximately 46 kDa, and its mRNA expression is coordinately regulated by the intestine-specific transcription factors Cdx2 and HNF1α. In normal hepatocytes, Cdx2 levels are extremely low, whereas elevated Cdx2 in hepatocellular carcinoma can lead to upregulated ACAT2 expression. Functionally, ACAT2 catalyzes the esterification of free cholesterol with long-chain acyl-CoA to generate cholesteryl esters, with its active site facing the endoplasmic reticulum lumen—in stark contrast to the cytosolic orientation of ACAT1. This unique topology determines that the primary physiological function of ACAT2 is to generate cholesteryl esters for the assembly and secretion of apolipoprotein B (apoB), participating in the absorption of dietary cholesterol in the intestine and providing the cholesteryl ester core for VLDL assembly in the liver. Gene knockout studies have confirmed that ACAT2-deficient mice show significantly restricted intestinal cholesterol absorption, markedly reduced cholesteryl ester content in hepatic and plasma lipoproteins, and are almost completely resistant to atherosclerosis in the ApoE-deficient background, establishing the critical role of ACAT2-derived cholesteryl esters in atherogenic lipoproteins. In addition, ACAT2 has been found to possess immunomodulatory functions in the tumor microenvironment, promoting M2-like polarization of tumor-associated macrophages to suppress CD8⁺ T cell activity, thereby driving tumor progression. Given its tissue distribution specificity and its central role in cholesterol absorption and the generation of atherogenic lipoproteins, ACAT2 has become an important target for drug development in the treatment of hypercholesterolemia and coronary heart disease.