Fatty acid-binding protein 5 (FABP5) is a cytoplasm protein that belongs to the fatty-acid binding protein (FABP) family of calycin superfamily. Fatty acid binding proteins are a family of small, highly conserved, cytoplasmic proteins that bind long-chain fatty acids. FABP5 can be expressed in keratinocytes, and is highly expressed in psoriatic skin. FABP5 has been shown to be involved in keratinocyte differentiation. FABP5 has high specificity for fatty acids, the highest affinity for C18 chain length. FABP5 can decrease the chain length or introduce double bonds to reduce the affinity.