Conserved Site

P-type trefoil, conserved site (IPR017957)

Short name: P_trefoil_CS


A cysteine-rich domain of approximately forty five amino-acid residues has been found in some extracellular eukaryotic proteins [PMID: 7820556, PMID: 9187350, PMID: 8518738, PMID: 8267796]. It is known as either the 'P', 'trefoil' or 'TFF' domain, and contains six cysteines linked by three disulphide bonds with connectivity 1-5, 2-4, 3-6. The domain has been found in a variety of extracellular eukaryotic proteins [PMID: 7820556, PMID: 8518738, PMID: 8267796], including protein pS2 (TFF1), a protein secreted by the stomach mucosa; spasmolytic polypeptide (SP) (TFF2), a protein of about 115 residues that inhibits gastrointestinal motility and gastric acid secretion; intestinal trefoil factor (ITF) (TFF3); Xenopus laevis stomach proteins xP1 and xP4; Xenopus integumentary mucins A.1 (FIM-A.1 or preprospasmolysin) and C.1 (FIM-C.1), proteins which may be involved in defence against microbial infections by protecting the epithelia from the external environment; Xenopus skin protein xp2 (or APEG); Zona pellucida sperm-binding protein B (ZP-B); intestinal sucrase-isomaltase (EC: / EC:, a vertebrate membrane bound, multifunctional enzyme complex which hydrolyses sucrose, maltose and isomaltose; and lysosomal alpha-glucosidase (EC:

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns