title: Role of the stem domain of matriptase in the interaction with its physiological inhibitor, hepatocyte growth factor activator inhibitor type I.
abstract: Matriptase is a type II transmembrane serine protease containing the non-catalytic domains (stem domain) and catalytic domain in the extra-cellular region. Our aim is to address the role of the stem domain in the interaction between matriptase and its physiological inhibitor, hepatocyte growth factor activator inhibitor type I (HAI-1). We prepared secreted variants of recombinant matriptase containing the entire extra-cellular domain (HL-matriptase) or only the catalytic domain (L-matriptase), and compared the inhibition activities of a cell membrane-anchored form of recombinant HAI-1 (maHAI-1) against the matriptase variants in the hydrolysis of peptidyl-4-methyl-coumaryl-7-amide (MCA) substrates. HL-matriptase and L-matriptase were inhibited by purified maHAI-1 with a similar extent when t-butyloxycarbonyl (Boc)-Gln-Ala-Arg-MCA (1) and acetyl-Lys-Thr-Lys-Gln-Leu-Arg-MCA (2) were used as substrates. However, HL-matriptase was inhibited more strongly than L-matriptase by maHAI-1 in the hydrolysis of Boc-[(2S)-2-amino-3-(benzyloxycarbonyl)propionyl]-Pro-Arg-MCA (3). These results show that the stem domain of matriptase facilitates the inhibitory interaction of this protease with maHAI-1 in the hydrolysis of substrate 3, although it has no effect in the hydrolysis of substrates 1 and 2. To our knowledge, this is the first evidence that the stem domain of matriptase can affect the interaction between this protease and HAI-1.
authors.affiliation: Laboratory of Enzyme Chemistry; and Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kojima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuzuki
authors.forename: Tohru
authors.initials: T
authors.lastname: Fushiki
authors.forename: Kuniyo
authors.initials: K
authors.lastname: Inouye
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D003374:Coumarins / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004789:Enzyme Activation; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008957:Models, Genetic; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: C502573:4-methyl-coumaryl-7-amide; D003374:Coumarins; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; C504592:Spint1 protein, rat; D012697:Serine Endopeptidases; C485595:matriptase