Premium
INVOLVEMENT OF PEPTIDOGLYCAN RECOGNITION PROTEIN L6 IN ACTIVATION OF IMMUNE DEFICIENCY PATHWAY IN THE IMMUNE RESPONSIVE SILKWORM CELLS
Author(s) -
Tanaka Hiromitsu,
Sagisaka Aki
Publication year - 2016
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21326
Subject(s) - peptidoglycan , biology , immune system , microbiology and biotechnology , signal transduction , gene knockdown , pattern recognition receptor , antimicrobial peptides , transmembrane domain , gene , bacteria , biochemistry , innate immune system , genetics
The immune deficiency (Imd) signaling pathway is activated by Gram‐negative bacteria for producing antimicrobial peptides (AMPs). In Drosophila melanogaster, the activation of this pathway is initiated by the recognition of Gram‐negative bacteria by peptidoglycan (PGN) recognition proteins (PGRPs), PGRP‐LC and PGRP‐LE. In this study, we found that the Imd pathway is involved in enhancing the promoter activity of AMP gene in response to Gram‐negative bacteria or diaminopimelic (DAP) type PGNs derived from Gram‐negative bacteria in an immune responsive silkworm cell line, Bm‐NIAS‐aff3. Using gene knockdown experiments, we further demonstrated that silkworm PGRP L6 (BmPGRP‐L6) is involved in the activation of E. coli or E. coli‐PGN mediated AMP promoter activation. Domain analysis revealed that BmPGRP‐L6 contained a conserved PGRP domain, transmembrane domain, and RIP homotypic interaction motif like motif but lacked signal peptide sequences. BmPGRP‐L6 overexpression enhances AMP promoter activity through the Imd pathway. BmPGRP‐L6 binds to DAP‐type PGNs, although it also binds to lysine‐type PGNs that activate another immune signal pathway, the Toll pathway in Drosophila. These results indicate that BmPGRP‐L6 is a key PGRP for activating the Imd pathway in immune responsive silkworm cells.