Mast cell tryptase from pig lungs triggers infection by pneumotropic Sendai and influenza A viruses. Purification and characterization.
A novel trypsin-type serine proteinase, which processes the precursors of the envelope fusion glycoproteins of pneumotropic Sendai and human influenza A viruses, was purified to homogeneity from pig lungs. On SDS/PAGE, the purified enzyme gave a protein band corresponding to about 32 kDa, and has an apparent molecular mass of 120 kDa, as determined by gel permeation chromatography. Immunohistochemical staining with antibodies against this enzyme revealed that the enzyme is located in pig lung mast cells. The N-terminal 44-amino-acid sequence of the enzyme exhibits about 80% identity with those of mast cell tryptases from other species. Of the inhibitors tested, di-isopropyl fluorophosphate, antipain, leupeptin, benzamidine and a few proteinaceous inhibitors, such as mucus protease inhibitor and aprotinin, inhibited this enzyme activity. Heparin stabilized the enzyme, but high-ionic-strength conditions did not, unlike for human mast cell tryptase. The purified enzyme efficiently processed the fusion glycoprotein precursor of Sendai virus and slowly processed hemagglutinin of human influenza A virus, and triggered the infectivity of Sendai virus in a dose-dependent manner, although human mast cell tryptase beta and rat mast cell tryptase (rat MCP-7) from lungs did not process these fusion glycoproteins at all. These results suggest that mast cell tryptase in pig lungs is the possible trigger of the pneumotropic virus infections.
Chen
Y
Y
Division of Enzyme Chemistry, Institute for Enzyme Research, University of Tokushima, Japan.
Shiota
M
M
Ohuchi
M
M
Towatari
T
T
Tashiro
J
J
Murakami
M
M
Yano
M
M
Yang
B
B
Kido
H
H
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002850:Chromatography, Gel; D053818:Chymases; D004789:Enzyme Activation / Q000187:drug effects; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009980:Influenza A virus / Q000502:physiology*; D008168:Lung / Q000166:cytology*; D008322:Mammals / Q000378:metabolism; D008407:Mast Cells / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats; D018108:Respirovirus / Q000502:physiology*; D016415:Sequence Alignment; D017385:Sequence Homology; D012697:Serine Endopeptidases / Q000302:isolation & purification / Q000502:physiology*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013045:Species Specificity; D013379:Substrate Specificity; D013552:Swine; D053802:Tryptases; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014774:Virulence; D014776:Virus Cultivation
C099057:F0 protein, Sendai virus; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D011498:Protein Precursors; D015842:Serine Proteinase Inhibitors; D014759:Viral Envelope Proteins; D006493:Heparin; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; C509223:Tpsab1 protein, rat; C509221:Tpsb2 protein, rat; D053802:Tryptases