Serpin-5 regulates prophenoloxidase activation and antimicrobial peptide pathways in the silkworm, Bombyx mori.
Insect Biochem Mol Biol
; 73: 27-37, 2016 06.
Article
em En
| MEDLINE
| ID: mdl-27084699
ABSTRACT
The prophenoloxidase (PPO) activation pathway and Toll pathway are two critical insect immune responses against microbial infection. Activation of these pathways is mediated by an extracellular serine protease cascade, which is negatively regulated by serpins. In this study, we found that the mRNA abundance of silkworm serpin-5 (BmSpn-5) increased dramatically in the fat body after bacterial infection. The expression level of antimicrobial peptides (AMPs), gloverin-3, cecropin-D and -E decreased in the silkworm larvae injected with recombinant BmSpn-5 protein. Meanwhile, the inhibition of beads melanization, systemic melanization and PPO activation by BmSpn-5 was also observed. By means of immunoaffinity purification and analysis by mass spectrometry, we identified that the silkworm clip domain serine proteases BmHP6 and BmSP21 form a complex with BmSpn-5, which suggests that BmHP6 and SP21 are the cognate proteases of BmSpn-5 and are essential in the serine protease cascade that activates the Toll and PPO pathways. Our study provides a comprehensive characterization of BmSpn-5 and sheds light on the multiple pathways leading to PPO activation and their regulation by serpins.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Bombyx
/
Transdução de Sinais
/
Serpinas
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Catecol Oxidase
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Proteínas de Insetos
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Precursores Enzimáticos
Limite:
Animals
Idioma:
En
Revista:
Insect Biochem Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
China