Mouse hepatocyte growth factor (HGF) activator inhibitor type 2 lacking the first Kunitz domain potently inhibits the HGF activator.
Hepatocyte growth factor activator inhibitor type 2 (HAI-2) is a serine proteinase inhibitor containing two Kunitz-type inhibitor domains, initially identified as a potent inhibitor of hepatocyte growth factor activator (HGFA). In a previous study (Biochem. Biophys. Res. Commun. 255, 740-748, 1999), we reported that a predominant transcript of mouse HAI-2 is a splicing variant lacking the first Kunitz domain (KD-1). Since KD-1 was reported to be responsible for the inhibition of HGFA in human HAI-2 and the second Kunitz domain (KD-2) of human HAI-2 was much less inhibitory against HGFA, it has been suggested that most of mouse HAI-2 may be ineffective in inhibiting HGFA. In this study, we have performed functional characterization of Kunitz domains in mouse HAI-2 by using recombinant proteins synthesized by Chinese hamster ovary cells without or with point mutation in the putative reactive site of each Kunitz domain. The results revealed that, unlike human HAI-2, KD-2 of mouse HAI-2 efficiently inhibits HGFA. Therefore, the major mouse HAI-2 protein that consists only of KD-2 can be a potent inhibitor of HGF activation in vivo.
Kataoka
Hiroaki
H
Second Department of Pathology, Miyazaki Medical College, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan.
Itoh
Hiroshi
H
Nuki
Yoshitsugu
Y
Hamasuna
Ryouichi
R
Naganuma
Seiji
S
Kitamura
Naomi
N
Shimomura
Takeshi
T
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides; D010940:Plant Proteins; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D014162:Transfection; D014360:Trypsin Inhibitor, Kunitz Soybean; D014361:Trypsin Inhibitors / Q000737:chemistry
C053865:Kunitz-type protease inhibitor, plant; D008562:Membrane Glycoproteins; D010455:Peptides; D010940:Plant Proteins; D012333:RNA, Messenger; C109148:SPINT2 protein, human; D015842:Serine Proteinase Inhibitors; D014361:Trypsin Inhibitors; D014360:Trypsin Inhibitor, Kunitz Soybean; C081092:HGF activator; D012697:Serine Endopeptidases