Identification of plasma proteinase complexes with serpin-3 in Manduca sexta.
Insect Biochem Mol Biol
; 42(12): 946-55, 2012 Dec.
Article
em En
| MEDLINE
| ID: mdl-23063421
ABSTRACT
Extracellular serine proteinase cascades stimulate prophenoloxidase (proPO) activation and antimicrobial peptide production in insect innate immune responses. Serpins in plasma regulate such cascades by selective inhibition of proteinases, in reactions which result in the formation of covalent serpin-proteinase complexes. We carried out experiments to identify plasma proteinases that are inhibited by Manduca sexta serpin-3, an immune-inducible serpin known to regulate proPO activation. Immunoaffinity chromatography, using antiserum to serpin-3, yielded serpin-3 complexes with proteinases identified by immunoblot analysis as prophenoloxidase-activating proteinase (PAP)-1, PAP-2, PAP-3, and hemolymph proteinase 8 (HP8). HP8 can cleave and activate the Toll ligand, Spätzle, leading to synthesis of antimicrobial peptides. Analysis by mass spectrometry of tryptic peptides derived from the serpin-3 complexes confirmed the presence of PAP-1, PAP-3, and HP8. Purified recombinant serpin-3 and active HP8 formed an SDS-stable complex in vitro. Identification of serpin-3-proteinase complexes in plasma provides insight into proteinase targets of serpin-3 and extends the understanding of serpin/proteinase function in the immune response of M. sexta.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Peptídeo Hidrolases
/
Serpinas
/
Manduca
/
Proteínas de Insetos
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Insect Biochem Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos