Distinct pathways of cell migration and antiapoptotic response to epithelial injury: structure-function analysis of human intestinal trefoil factor.
The trefoil peptide intestinal trefoil factor (ITF) plays a critical role in the protection of colonic mucosa and is essential to restitution after epithelial damage. These functional properties are accomplished through coordinated promotion of cell migration and inhibition of apoptosis. ITF contains a unique three-looped trefoil motif formed by intrachain disulfide bonds among six conserved cysteine residues, which is thought to contribute to its marked protease resistance. ITF also has a seventh cysteine residue, which permits homodimer formation. A series of cysteine-to-serine substitutions and a C-terminally truncated ITF were made by PCR site-directed mutagenesis. Any alteration of the trefoil motif or truncation resulted in loss of protease resistance. However, neither an intact trefoil domain nor dimerization was required to promote cell migration. This pro-restitution activity correlated with the ability of the ITF mutants to activate mitogen-activated protein (MAP) kinase independent of phosphorylation of the epidermal growth factor (EGF) receptor. In contrast, only intact ITF retained both phosphatidylinositol 3-kinase and the EGF receptor-dependent antiapoptotic effect in HCT116 and IEC-6 cells. The inability to block apoptosis correlated with a loss of trefoil peptide-induced transactivation of the EGF receptor or Akt kinase in HT-29 cells. In addition to defining structural requirements for the functional properties of ITF, these findings demonstrate that distinct intracellular signaling pathways mediate the effects of ITF on cell migration and apoptosis.
Kinoshita
K
K
Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
Taupin
D R
DR
Itoh
H
H
Podolsky
D K
DK
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D003110:Colonic Neoplasms; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004848:Epithelium / Q000293:injuries / Q000473:pathology; D005419:Flavonoids / Q000494:pharmacology; D006133:Growth Substances / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008969:Molecular Sequence Data; D009077:Mucins; D009124:Muscle Proteins; D009479:Neuropeptides; D010434:Pepsin A / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D013879:Thioredoxins / Q000235:genetics / Q000302:isolation & purification; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D014357:Trypsin / Q000378:metabolism; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D005419:Flavonoids; D006133:Growth Substances; D009077:Mucins; D009124:Muscle Proteins; D009479:Neuropeptides; D010455:Peptides; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; C099037:TFF3 protein, rat; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D013879:Thioredoxins; C494918:AKT1 protein, human; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D014357:Trypsin; D010434:Pepsin A; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one