Fatty acid binding proteins are a family of small, highly conserved, cytoplasmic proteins (14-15kDa) that bind long chain fatty acids, their CoA derivatives, billiruben, organic anions and other small hydrophobic molecules. E-FABP (or FABP-5) is thought work in conjunction with A-FABP to facilitate fatty acid efflux from adipocytes. E-FABP may also be involved in keratinocyte differentiation.