TREFOIL PEPTIDES - FROM STRUCTURE TO FUNCTION

The unique structure in which six cysteine residues in a sequence of 3 8 or 39 amino acid residues form three disulphide bonds in a 1-5, 2-4 and 3-6 configuration constitutes the basic elements of a trefoil doma in. Today three mammalian trefoil factors (TFF1. TFF2 and TFF3) contai ning one or two trefoil domains are known. Trefoil factors are usually associated with the mucin layer of the gastrointestinal tract. Early studies on trefoil factors concentrated on structure elucidation and s ites of expression in health and disease. whereas studies over the las t 3-5 years have focused on the mechanism of action and the search for specific receptors. This review summarises our present knowledge of t refoil peptide structures, their sites of expression, and their protec tion and repair functions, with a focus on the mechanism by which thes e peptides exert their biological function.