Human intestinal TFF3 forms disulfide-linked heteromers with the mucus-associated FCGBP protein and is released by hydrogen sulfide.
TFF3 is a secretory peptide belonging to the trefoil factor family with a predicted size of 59 amino acid residues containing seven cysteine residues. It is predominantly expressed in intestinal goblet cells where it plays a key role in mucosal regeneration and repair processes. In the course of these studies, human colonic TFF3 was shown to exist mainly as a high molecular weight heteromer. Purification of this heteromer and characterization by LC-ESI-MS/MS analysis identified the IgG Fc binding protein (FCGBP) as the disulfide-linked partner protein of TFF3. FCGBP is a constituent of intestinal mucus secreted by goblet cells. Furthermore, low amounts of TFF3/monomer and only little TFF3/dimer were detected in human colonic extracts. Here, we show that these TFF3 forms can be released from the purified TFF3-FCGBP heteromer complex in vitro by reduction with hydrogen sulfide (H(2)S). Such a mechanism would be in line with the high H(2)S concentrations reported to occur in the lumen of the colon. Of special note, this points to intestinal mucus as a reservoir for a biologically active peptide. Also proteolytic processing of FCGBP was observed which is in line with multiple autocatalytic cleavages as proposed earlier by Johansson et al. (J. Proteome Res. 2009 , 8 , 3549 - 3557).
Albert
Timo K
TK
Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
Laubinger
Werner
W
Müller
Stefan
S
Hanisch
Franz-Georg
FG
Kalinski
Thomas
T
Meyer
Frank
F
Hoffmann
Werner
W
D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000378:metabolism; D002850:Chromatography, Gel; D003106:Colon / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism*; D009093:Mucus / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D055503:Protein Multimerization; D040901:Proteomics / Q000379:methods; D014020:Tissue Extracts / Q000737:chemistry; D000071165:Trefoil Factor-3
D015815:Cell Adhesion Molecules; C106607:FCGBP protein, human; D010446:Peptide Fragments; D010455:Peptides; C082495:TFF3 protein, human; D014020:Tissue Extracts; D000071165:Trefoil Factor-3; D006862:Hydrogen Sulfide