Characterization of the necrotic protein that regulates the Toll-mediated immune response in Drosophila.
Necrotic (Nec) is an important component of the proteolytic cascade that activates the Toll-mediated immune response in Drosophila. The Nec protein is a member of the serpin (SERine Protease INhibitor) superfamily and is thought to regulate the cascade by inhibiting the serine protease Persephone. Nec was expressed in Escherichia coli, and the purified protein folded to the active native conformation required for protease inhibitory activity. Biochemical analysis showed that Nec had a broad inhibitory specificity and inhibited elastase, thrombin, and chymotrypsin-like proteases. It did not inhibit trypsin or kallikrein. These data show that Necrotic is likely to inhibit a wide range of proteases in Drosophila and that Nec has the specificity requirements to act as the physiological inhibitor of Persephone in vivo.
Robertson
Andrew S
AS
Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, United Kingdom.
Belorgey
Didier
D
Lilley
Kathryn S
KS
Lomas
David A
DA
Gubb
David
D
Dafforn
Timothy R
TR
D000818:Animals; D003001:Cloning, Molecular; D004330:Drosophila / Q000276:immunology* / Q000502:physiology; D029721:Drosophila Proteins / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D010450:Endopeptidases / Q000378:metabolism; D004926:Escherichia coli / Q000276:immunology; D007700:Kinetics; D008070:Lipopolysaccharides / Q000276:immunology; D008322:Mammals; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D017384:Sequence Deletion; D015843:Serpins / Q000276:immunology / Q000502:physiology*; D051193:Toll-Like Receptors
D029721:Drosophila Proteins; D008070:Lipopolysaccharides; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D015843:Serpins; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors; C417282:nec protein, Drosophila; D010450:Endopeptidases