The overall goal of the program is to elucidate the mechanisms of regulation of cholesterol homeostasis in the liver. Major emphasis is on the regulation of cholesterol esterification by the enzyme acyl coenzyme A: cholesterol acyltransferase (ACAT). This proposal is aimed at preparation of specific antibodies to ACAT in order to study the detailed regulation of this enzyme at the molecular, biochemical and physiological levels. Kinetic analyses of microsomal ACAT will be used to gain information on the relative importance of different modes of regulation of the enzyme. The antibodies will be used to examine regulation of ACAT by synthesis, degradation, phosphorylation; to investigate subcellular localization of ACAT in the liver and its localization in the intestine; and to study the molecular biology of the enzyme. These studies, by describing how cholesterol esterification in the liver is regulated, may help us to understand the pathologies of both atherosclerosis and cholelithiasis and may enable us to devise rational means of preventing or alleviating these diseases.
