Proteolytic activation of a single-chain precursor of hepatocyte growth factor by extracellular serine-protease.
Hepatocyte growth factor (HGF) is biosynthesized as a single-chain precursor (pro-HGF) and is proteolytically processed to a two-chain mature form. When MRC-5 fibroblasts were pulse-radiolabeled under serum-free conditions, pro-HGF was the predominant molecular form of HGF in the culture medium. CHO cells transfected with an expression plasmid containing a full-size human HGF cDNA produced pro-HGF when these cells were cultured in serum-free medium. These findings suggest that HGF is secreted as a pro-form, which is then converted to a two-chain form by extracellular protease. Single-chain HGF exhibited mitogenic activity on cultured hepatocytes, with a potency similar to that of mature HGF, but this activity was remarkably inhibited by leupeptin. We postulate that inactive pro-HGF is converted to an active two-chain form by a leupeptin-sensitive serine-protease expressed by hepatocytes. Neither plasminogen activators nor plasmin showed any processing activity of pro-HGF in vitro.
Mizuno
K
K
Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
Takehara
T
T
Nakamura
T
T
D000818:Animals; D001345:Autoradiography; D016466:CHO Cells; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D006224:Cricetinae; D003545:Cysteine / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005341:Fibrinolysin / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008099:Liver / Q000378:metabolism*; D008168:Lung; D008715:Methionine / Q000378:metabolism; D010957:Plasmids; D011498:Protein Precursors / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D011499:Protein Processing, Post-Translational; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis; D012697:Serine Endopeptidases / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D010959:Tissue Plasminogen Activator / Q000494:pharmacology; D014162:Transfection; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology
D007976:Leupeptins; D011498:Protein Precursors; D011994:Recombinant Proteins; D013462:Sulfur Radioisotopes; D017228:Hepatocyte Growth Factor; D004247:DNA; D008715:Methionine; D012697:Serine Endopeptidases; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; C032854:leupeptin; D003545:Cysteine