Isolation and characterization of putative trefoil peptide receptors.
Mammalian trefoil factors (TFFs) constitute a group of three peptides (TFF1, TFF2 and TFF3) widely distributed in the gastrointestinal tract. Although a mucosal protection/healing effect of these peptides is well documented the mechanism of action is still unknown. A mucosal membrane extract was prepared from porcine stomach scrapings and incubated with a gel containing immobilized porcine TFF2. The affinity gel material was specifically eluted with a neutral buffer containing a high concentration of the ligand (porcine TFF2). A subsequent SDS-gel electrophoresis showed one protein with a MW of approximately 220 kDa and three proteins with MW around 140 kDa. The proteins were analyzed by trypsin digestion followed by mass spectrometric sequencing of tryptic fragments. In this way a 140-kDa beta subunit of fibronectin receptor and a 224-kDa CRP-Ductin gene product were identified. The CRP-Ductin gene product (also named MUCLIN), which is expressed in the intestinal crypts, is characterized by being a membrane protein with a short cytoplasmic region, a transmembrane domain and a large extracellular region. This protein thus fulfils some of the criteria for being a TFF receptor or a TFF binding protein.
Thim
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L
Department of Protein Chemistry, Health Care Discovery, Novo Nordisk A/S, DK-2880, Bagsvaerd, Denmark. lth@novo.dk
Mørtz
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D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005260:Female; D005753:Gastric Mucosa / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D009077:Mucins / Q000737:chemistry* / Q000302:isolation & purification; D018000:Receptors, Peptide / Q000737:chemistry* / Q000302:isolation & purification; D012967:Sodium Dodecyl Sulfate; D013552:Swine; D000071164:Trefoil Factor-2; D025521:Tumor Suppressor Proteins
D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; C114202:Dmbt1 protein, mouse; D009077:Mucins; D018000:Receptors, Peptide; C000604007:TFF2 protein, human; D000071164:Trefoil Factor-2; D025521:Tumor Suppressor Proteins; C108345:trefoil factor receptor; D012967:Sodium Dodecyl Sulfate