Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Autoradiography
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CHO Cells
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Cell Division / drug effects
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Cell Line
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Cricetinae
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Cysteine / metabolism
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DNA / genetics
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Electrophoresis, Polyacrylamide Gel
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Fibrinolysin / pharmacology
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Hepatocyte Growth Factor / biosynthesis*
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Hepatocyte Growth Factor / genetics
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Humans
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Leupeptins / pharmacology
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Liver / metabolism*
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Lung
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Methionine / metabolism
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Plasmids
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Protein Precursors / biosynthesis*
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Protein Precursors / genetics
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Protein Precursors / isolation & purification
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Protein Processing, Post-Translational*
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Rats
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Recombinant Proteins / biosynthesis
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Serine Endopeptidases / metabolism*
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Sulfur Radioisotopes
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Tissue Plasminogen Activator / pharmacology
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Transfection
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Urokinase-Type Plasminogen Activator / pharmacology
Substances
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Leupeptins
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Protein Precursors
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Recombinant Proteins
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Sulfur Radioisotopes
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Hepatocyte Growth Factor
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DNA
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Methionine
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Serine Endopeptidases
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Tissue Plasminogen Activator
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Fibrinolysin
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Urokinase-Type Plasminogen Activator
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leupeptin
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Cysteine