title: Cloning and characterization of a transmembrane-type serine protease from rat kidney, a new sodium channel activator.
abstract: We have cloned the gene of a new transmembrane-type serine protease from rat kidney, which activates sodium channels. The amino acid sequence deduced from a full-length cDNA revealed that transmembrane serine protease-1 (TMSP-1) is a member of the clan SA/family S1 of serine proteases, comprising a 30 amino acid prepropeptide, a mature form sequence of 274 amino acids starting with the Ile-Val-Gly-Gly-Gln motif, and a common catalytic triad of serine proteases. The hydrophobic amino acid sequence in the carboxy-terminus of this enzyme suggests that it is a glycosylphosphatidylinositol-anchored protein. As revealed by quantitative reverse transcription-polymerase chain reaction analysis, it is highly expressed in kidney, small intestine, and stomach, and moderately expressed in lung, thymus, spleen and skin. The recombinant protease had an optimal pH at 9.0, selectively cleaved synthetic peptide substrates of trypsin, and was inhibited by aprotinin, leupeptin and benzamidine. Immunohistochemical studies revealed that this protease is predominantly expressed in cells from collecting ducts of the renal medulla. We also demonstrate that a C-terminally truncated variant of TMSP-1 significantly activates the epithelial sodium channel, and that its mRNA levels are upregulated by aldosterone. These observations suggest that it is a new member of the trypsin-type transmembrane proteases, which regulate sodium balance by activating the epithelial sodium channel.
authors.affiliation: Division of Enzyme Chemistry, Institute for Enzyme Research, The University of Tokushima, Kuramoto-cho 3-18-15, Tokushima 770-8503, Japan.
authors.forename: Yuushi
authors.initials: Y
authors.lastname: Okumura
authors.forename: Mai
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Ping
authors.initials: P
authors.lastname: Cui
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shiota
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Masataka
authors.initials: M
authors.lastname: Adachi
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Kitamura
authors.forename: Kimio
authors.initials: K
authors.lastname: Tomita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kido
mesh_terms: D000450:Aldosterone / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis / Q000737:chemistry; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D007668:Kidney / Q000737:chemistry / Q000201:enzymology*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D015222:Sodium Channels / Q000096:biosynthesis / Q000378:metabolism*; D014162:Transfection; D014357:Trypsin
chemical_list: D018076:DNA, Complementary; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D015222:Sodium Channels; D000450:Aldosterone; D012697:Serine Endopeptidases; C492507:transmembrane serine protease-1, rat; D014357:Trypsin