Lipid transport protein in adipocytes. Binds both long chain fatty acids and retinoic acid. Delivers long-chain fatty acids and retinoic acid to their cognate receptors in the nucleus (By similarity). FABPs are important elements related to the hibernating state in mammals (PubMed:11779641). Monomer (By similarity). Homodimer. Interacts with PPARG (By similarity). Depending on the nature of the ligand, a conformation change exposes a nuclear localization motif and the protein is transported into the nucleus. Subject to constitutive nuclear export. Up-regulated during hibernation in brown adipose tissue. Forms a beta-barrel structure that accommodates the hydrophobic ligand in its interior. Belongs to the calycin superfamily. Fatty-acid binding protein (FABP) family.