pS2/TFF1 interacts directly with the VWFC cysteine-rich domains of mucins.
OBJECTIVE
Trefoil factors (TFFs) are secreted gastrointestinal proteins that have been shown to protect and promote healing of the gastrointestinal tract. Moreover, pS2/TFF1 is essential for normal differentiation of the gastric mucosa because deficient mice develop antropyloric adenomas. To date, it is unclear how TFFs mediate their functions.


METHODS
Using the yeast 2-hybrid system, we attempted to identify murine TFF1 interacting proteins by screening a stomach and duodenum complementary DNA (cDNA) expression library.


RESULTS
Four positive clones were isolated. Sequence and expression studies showed that they corresponded to the murine counterpart of human cDNA sequences encoding carboxy-terminal fragments of mMuc2 (489 residues) and mMuc5AC (427, 430, and 894 residues) mucin proteins. Mutagenesis experiments showed that TFF1 interacts with the 2 mucins through binding with their VWFC1 and VWFC2 (von Willebrand factor C) cysteine-rich domains.


CONCLUSIONS
These results show that the gastrointestinal protective effect of TFF1, and presumably of the other TFFs, is caused at least partially by their participation, via mucin binding, in the correct organization of the mucous layer that protects the apical side of the mucosa from deleterious luminal agents.
Tomasetto
C
C
Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM Unité 184/ULP, Illkirch, France.
Masson
R
R
Linares
J L
JL
Wendling
C
C
Lefebvre
O
O
Chenard
M P
MP
Rio
M C
MC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002999:Clone Cells; D003545:Cysteine; D004386:Duodenum / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism*; D006822:Hybrid Cells; D051379:Mice; D008969:Molecular Sequence Data; D009077:Mucins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009124:Muscle Proteins; D009479:Neuropeptides; D010455:Peptides / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D015003:Yeasts; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism*
D006133:Growth Substances; D009077:Mucins; D009124:Muscle Proteins; D009479:Neuropeptides; D010455:Peptides; D012333:RNA, Messenger; C099037:TFF3 protein, rat; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D014841:von Willebrand Factor; D003545:Cysteine