FABP

Fatty acid-binding proteins (FABPs) are members of the intracellular lipid-binding protein (iLBP) family and are involved in reversibly binding intracellular hydrophobic ligands and trafficking them throughout cellular compartments, including the peroxisomes, mitochondria, endoplasmic reticulum and nucleus. FABPs have broad specificity, including the ability to bind long-chain (C16-C20) fatty acids, eicosanoids, bile salts and peroxisome proliferators. FABPs demonstrate strong evolutionary conservation and are present in a spectrum of species including Drosophila melanogaster, Caenorhabditis elegans, mouse and human.

FABPs are widely expressed throughout the body and play an integral role in a multitude of physiological processes such as lipid metabolism, inflammation and neuronal signaling. FABPs of the mammalian central and peripheral nervous systems have been shown to facilitate the intracellular transport of NAEs, particularly the endocannabinoid arachidonoyl ethanolamide (anandamide, AEA), as well as catabolism by the endoplasmic reticulum-localized enzyme fatty acid amide hydrolase (FAAH).

Most mammals produce 12 distinct subtypes of FABPs, although humans produce up to 10. These include liver-(L-FABP, FABP1), intestine-(I-FABP, FABP2), heart-(H-FABP, FABP3), adipocyte-(A-FABP, FABP4), epidermal-(E-FABP, FABP5), ileal-(Il-FABP, FABP6), brain-(B-FABP, FABP7), myelin-(M-FABP, FABP8), testis-(T-FABP, FABP9) and FABP12, and three of which are expressed in the brain, including FABP3, FABP5 and FABP7.

FABPs have diverse and highly specified roles in regulating the metabolism and actions of the ligands they bind. They are important targets for drug development and therapy for many metabolic diseases.