Peptidoglycan Recognition Proteins Involved in 1,3-β -D-Glucan-dependent Prophenoloxidase Activation System of Insect

Mi Hee Lee, Tsukasa Osaki, Joo Young Lee, Min Ji Baek, Rong Zhang, Ji Won Park, Shun Ichiro Kawabata, Kenneth Söderhäll, Bok Luel Lee

Research output: Contribution to journalArticlepeer-review

88 Citations (Scopus)


The prophenoloxidase (proPO) cascade is a major innate immune response in invertebrates, which is triggered into its active form by elicitors, such as lipopolysaccharide, peptidoglycan, and 1,3-β-D-glucan. A key question of the proPO system is how pattern recognition proteins recognize pathogenic microbes and subsequently activate the system. To investigate the biological function of 1,3-β-D-glucan pattern recognition protein in the proPO cascade system, we isolated eight different 1,3-β-D-glucan-binding proteins from the hemolymph of large beetle (Holotrichia diomphalia) larvae by using 1,3-β-D-glucan immobilized column. Among them, a 20- and 17-kDa protein (referred to as Hd-PGRP-1 and Hd-PGRP-2) show high sequence identity with the short forms of peptidoglycan recognition proteins (PGRPs-S) from human and Drosophila melanogaster. To be able to characterize the biochemical prop. erties of these two proteins, we expressed them in Drosophila S2 cells. Hd-PGRP-1 and Hd-PGRP-2 were found to specifically bind both 1, 3-β-D-glucan and peptidoglycan. By BIAcore analysis, the minimal 1,3-β-D-glucan structure required for binding to Hd-PGRP-1 was found to be laminaritetraose. Hd-PGRP-1 increased serine protease activity upon binding to 1,3-β-D-glucan and subsequently induced the phenoloxidase activity in the presence of both 1,3-β-D-glucan and Ca2+, but no phenoloxidase activity was elicited under the same conditions in the presence of peptidoglycan and Ca2+. These results demonstrate that Hd-PGRP-1 can serve as a receptor for 1,3-β-D-glucan in the insect proPO activation system.

Original languageEnglish
Pages (from-to)3218-3227
Number of pages10
JournalJournal of Biological Chemistry
Issue number5
Publication statusPublished - Jan 30 2004

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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