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An ML protein from the silkworm Bombyx mori may function as a key accessory protein for lipopolysaccharide signaling.

Authors :
Zhang RN
Ren FF
Zhou CB
Xu JF
Yi HY
Ye MQ
Deng XJ
Cao Y
Yu XQ
Yang WY
Source :
Developmental and comparative immunology [Dev Comp Immunol] 2018 Nov; Vol. 88, pp. 94-103. Date of Electronic Publication: 2018 Jul 18.
Publication Year :
2018

Abstract

Lipopolysaccharide (LPS) is a common component of the outermost cell wall in Gram-negative bacteria. In mammals, LPS serves as an endotoxin that can be recognized by a receptor complex of TLR4 (Toll-like receptor 4) and MD-2 (myeloid differentiation-2) and subsequently induce a strong immune response to signal the release of tumor necrosis factor (TNF). In Drosophila melanogaster, no receptors for LPS have been identified, and LPS cannot activate immune responses. Here, we report a protein, BmEsr16, which contains an ML (MD-2-related lipid-recognition) domain, may function as an LPS receptor in the silkworm Bombyx mori. We showed that antibacterial activity in the hemolymph of B. mori larvae was induced by Escherichia coli, peptidoglycan (PGN) and LPS and that the expression of antimicrobial peptide genes was also induced by LPS. Furthermore, both the expression of BmEsr16 mRNA in the fat body and the expression of BmEsr16 protein in the hemolymph were induced by LPS. Recombinant BmEsr16 bound to LPS and lipid A, as well as to PGN, lipoteichoic acid, but not to laminarin or mannan. More importantly, LPS-induced immune responses in the hemolymph of B. mori larvae were blocked when the endogenous BmEsr16 protein was neutralized by polyclonal antibody specific to BmEsr16. Our results suggest that BmEsr16 may function as a key accessory protein for LPS signaling in B. mori.<br /> (Copyright © 2018. Published by Elsevier Ltd.)

Details

Language :
English
ISSN :
1879-0089
Volume :
88
Database :
MEDLINE
Journal :
Developmental and comparative immunology
Publication Type :
Academic Journal
Accession number :
30009928
Full Text :
https://doi.org/10.1016/j.dci.2018.07.012