Acot13, also known as Thioesterase superfamily member 2 (Them2), is an acyl-CoA thioesterase that hydrolyzes fatty acyl-CoAs, especially long-chain fatty acyl-CoAs. It is associated with mitochondria and is involved in pathways such as lipid biosynthesis, gene transcription, and signal transduction, playing important roles in energy metabolism and cell function [1,2,3].

In mouse models, Them2 knockout (Them2-/-) mice showed increased adaptive responses in physical activity, food consumption, and energy expenditure in response to short-term cold exposure, along with reduced lipid droplets, mitochondrial ultrastructure alterations, and increased thermogenic gene expression in brown adipose tissue, indicating its role in suppressing adaptive increases in energy expenditure [1]. In liver, Them2-/-mice had changes in mitochondrial thioesterase activity, fatty acyl-CoA and free fatty acid concentrations, and decreased hepatic glucose production, suggesting it regulates hepatic lipid and glucose metabolism [2].

In conclusion, Acot13 plays essential roles in regulating energy metabolism, including thermogenesis and hepatic metabolism. Studies on Acot13 knockout mouse models have provided valuable insights into its functions in these biological processes, which may be relevant to understanding diseases related to metabolic disorders.