title: Roles of CUB and LDL receptor class A domain repeats of a transmembrane serine protease matriptase in its zymogen activation.
abstract: Matriptase is a type II transmembrane serine protease containing two complement proteases C1r/C1s-urchin embryonic growth factor-bone morphogenetic protein domains (CUB repeat) and four low-density lipoprotein receptor class A domains (LDLRA repeat). The single-chain zymogen of matriptase has been found to exhibit substantial protease activity, possibly causing its own activation (i.e. conversion to a disulfide-linked two-chain fully active form), although the activation seems to be mediated predominantly by two-chain molecules. Our aim was to assess the roles of CUB and LDLRA repeats in zymogen activation. Transient expression studies of soluble truncated constructs of recombinant matriptase in COS-1 cells showed that the CUB repeat had an inhibitory effect on zymogen activation, possibly because it facilitated the interaction of two-chain molecules with a matriptase inhibitor, hepatocyte growth factor activator inhibitor type-1. By contrast, the LDLRA repeat had a promoting effect on zymogen activation. The effect of the LDLRA repeat seems to reflect its ability to increase zymogen activity. The proteolytic activities were higher in pseudozymogen forms of recombinant matriptase containing the LDLRA repeat than in a pseudozymogen without the repeat. Our findings provide new insights into the roles of these non-catalytic domains in the generation of active matriptase.
authors.affiliation: Division of Food Science and Biotechnology, Laboratory of Enzyme Chemistry, Graduate School of Agriculture, Kyoto University, Oiwake-cho, Kitashirakawa, Kyoto City 606-8502, Japan. inouye@kais.kyoto-u.ac.jp
authors.forename: Kuniyo
authors.initials: K
authors.lastname: Inouye
authors.forename: Marie
authors.initials: M
authors.lastname: Tomoishi
authors.forename: Makoto
authors.initials: M
authors.lastname: Yasumoto
authors.forename: Yuka
authors.initials: Y
authors.lastname: Miyake
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
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016466:CHO Cells; D019556:COS Cells; D002522:Chlorocebus aethiops; D015923:Complement C1r / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003173:Complement C1s / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D051381:Rats; D011973:Receptors, LDL / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D012617:Sea Urchins; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins; D004792:Enzyme Precursors; D008562:Membrane Glycoproteins; D050505:Mutant Proteins; D011973:Receptors, LDL; D011993:Recombinant Fusion Proteins; C504592:Spint1 protein, rat; D012697:Serine Endopeptidases; C485593:St14 protein, rat; C485595:matriptase; D015923:Complement C1r; D003173:Complement C1s