title: Molecular collaborations between serpins and trefoil factor promote endodermal cell growth and gastrointestinal differentiation in budding tunicates.
abstract: We present evidence supporting novel collaborations between the serine protease inhibitor (serpin) and the trefoil factor during the budding stage of the tunicate Polyandrocarpa misakiensis. Using a maltose-binding protein/P-serpin fusion protein, two polypeptides of 40 kDa and 45 kDa were pulled down from Polyandrocarpa homogenates. Based on their partial amino acid sequence data, a single cDNA (928 bp) was cloned. It encodes a polypeptide that has five tandem repeats of a trefoil consensus motif. Thus, we termed the cDNA P-trefoil. Both P-trefoil and P-serpin were expressed exclusively by coelomic cells during budding. P-Trefoil was expressed mainly by coelomic cells throughout the asexual life cycle of Polyandrocarpa, while P-Serpin was localized particularly in coelomic cells and in the extracellular matrix in developing buds. The native P-Trefoil protein showed aminopeptidase activity. It induced cell growth in cultured Polyandrocarpa cells at a concentration of 8 microg/mL. P-Serpin reinforced this activity of P-Trefoil. Further, a mixture of P-Trefoil and P-Serpin exhibited the in vitro induction of a gut-specific alkaline phosphatase. These results show for the first time that a serpin can interact with a trefoil factor to play a role in the cellular growth and differentiation of the gastric epithelium.
authors.affiliation: Laboratory of Molecular and Cellular Biotechnology, Faculty of Science, Kochi University, Kochi 780-8520, Japan. kazuk@cc.kochi-u.ac.jp
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kawamura
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kariya
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Ono
authors.forename: Akira
authors.initials: A
authors.lastname: Muramoto
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ohta
authors.forename: Shigeki
authors.initials: S
authors.lastname: Fujiwara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D002846:Chromatography, Affinity; D004064:Digestive System / Q000196:embryology; D004707:Endoderm / Q000166:cytology*; D004848:Epithelium / Q000196:embryology; D050437:Genes, Developmental; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012100:Reproduction, Asexual; D015843:Serpins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000071164:Trefoil Factor-2; D014561:Urochordata / Q000196:embryology*
chemical_list: D010455:Peptides; D015843:Serpins; D000071164:Trefoil Factor-2; D010447:Peptide Hydrolases