Members of the trefoil family are characterized by having at least one copy of the trefoil motif, a 40-amino acid domain that contains three conserved disulfides. They are stable secretory proteins expressed in gastrointestinalmucosa. Their functions are not defined, but they may protect the mucosa from insults, stabilize the mucus layer and affect healing of the epithelium. The encoded protein inhibits gastric acid secretion. This gene and two other related trefoil family member genes are found in a cluster on chromosome 21.[7]
All human trefoil factors are lectins that interact specifically with the disaccharide GlcNAc-α-1,4-Gal.[8] This disaccharide is an unusual glycotope that is only known to exist on the large, heavily glycosylated, mucins in the mucosa. By cross-linking mucins through the bivalent binding of this glycotope, the trefoil factors are then able to reversible modulate the thickness and viscosity of the mucus.[8]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Tomasetto C, Rockel N, Mattei MG, Fujita R, Rio MC (Sep 1992). "The gene encoding the human spasmolytic protein (SML1/hSP) is in 21q 22.3, physically linked to the homologous breast cancer marker gene BCEI/pS2". Genomics. 13 (4): 1328–30. doi:10.1016/0888-7543(92)90059-2. PMID1505966.
May FE, Westley BR (1997). "Close physical linkage of the genes encoding the pNR-2/pS2 protein and human spasmolytic protein (hSP)". Hum. Genet. 99 (3): 303–7. doi:10.1007/s004390050362. PMID9050913. S2CID22603186.
Seib T, Blin N, Hilgert K, et al. (1997). "The three human trefoil genes TFF1, TFF2, and TFF3 are located within a region of 55 kb on chromosome 21q22.3". Genomics. 40 (1): 200–2. doi:10.1006/geno.1996.4511. PMID9070946.
Berry A, Scott HS, Kudoh J, et al. (2001). "Refined localization of autosomal recessive nonsyndromic deafness DFNB10 locus using 34 novel microsatellite markers, genomic structure, and exclusion of six known genes in the region". Genomics. 68 (1): 22–9. doi:10.1006/geno.2000.6253. PMID10950923.
Bulitta CJ, Fleming JV, Raychowdhury R, et al. (2002). "Autoinduction of the trefoil factor 2 (TFF2) promoter requires an upstream cis-acting element". Biochem. Biophys. Res. Commun. 293 (1): 366–74. doi:10.1016/S0006-291X(02)00199-7. PMID12054609.