Journal of Biochemistry Advance Access originally published online on March 10, 2009
Journal of Biochemistry 2009 145(6):783-790; doi:10.1093/jb/mvp036
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Role of the Stem Domain of Matriptase in the Interaction with its Physiological Inhibitor, Hepatocyte Growth Factor Activator Inhibitor Type I
1Laboratory of Enzyme Chemistry; and 2Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
*To whom correspondence should be addressed. Tel: +81-75-753-6266, Fax: +81-75-753-6265, E-mail: inouye{at}kais.kyoto-u.ac.jp
Received December 30, 2008; Accepted February 23, 2009
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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.
Key Words: hepatocyte growth factor activator inhibitor type I, inhibitory interaction, matriptase, membrane-type serine protease, stem domain
Abbreviations: BEK, bovine enterokinase; Boc, t-butyloxycarbonyl; CHO, Chinese hamster ovary; CUB domain, complement factor 1R–urchin embryonic growth factor–bone morphogenetic protein domain; HAI-1, hepatocyte growth factor activator inhibitor type I; HGF, hepatocyte growth factor; HRP, horseradish peroxidase; LDLRA domain, low-density lipoprotein receptor A module domains; MCA, 4-methyl-coumaryl-7-amide; r-EK, recombinant enterokinase; sc-uPA, single-chain urokinase-type plasminogen activator; SEA domain, sea-urchin sperm protein–enterokinase–agrin domain