a lipid transport protein that is the predominant fatty acid binding protein found in adipocytes. Also expressed in macrophages. Binds both long chain fatty acids and retinoic acid. Delivers long-chain fatty acids and retinoic acid to their cognate receptors in the nucleus. Homodimer. Forms a beta-barrel structure that accommodates hydrophobic ligands in its interior. Interacts with PPARG. Monomer. FABP4 knockout mice fed a high-fat and high-calorie diet become obese but develop neither insulin resistance nor diabetes, suggesting that this protein might be a link between obesity and insulin resistance and diabetes. Mice deficient in both FABP4 and ApoE show protection against atherosclerosis when compared with mice deficient only in ApoE. Mice carrying a FABP4 genetic variant exhibit both reduced FABP4 expression and a reduced potential for developing type 2 diabetes and coronary heart disease. A related study in humans indicated a similar pattern, suggesting that FABP4 may be a potential therapeutic target in the treatment of these disorders. Belongs to the calycin superfamily,fatty-acid binding protein (FABP) family. Note: This description may include information from UniProtKB.