Characterization and expression of a novel human fatty acid-binding protein: the epidermal type (E-FABP)

Using PAGE--Autoradioblotting technique we have characterized an E--FABP in human epidermal cells that is distinct from liver-, heart-, intestine- and adipose tissue-FABPs. FABP radiobinding analysis was performed directly on protein extracts without prior partial purification. E-FABP has a Mr of approximately 15 kDa and binds oleic acid with high affinity but does not bind all-trans-, 13-cis- and 9-cis-retinoic acid nor all-trans-retinol. Expression levels of E-FABP were low in normal epidermis, higher in human cultured keratinocytes and still higher in psoriasis, a disease characterized by abnormal epidermal differentiation. These findings suggest that epidermal cells may have a distinct fatty acid metabolism compared to other tissues.