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Park JW, Kim CH, Kim JH, Je BR, Roh KB, Kim SJ, Lee HH, Ryu JH, Lim JH, Oh BH, Lee WJ, Ha NC, Lee BL. Clustering of peptidoglycan recognition protein-SA is required for sensing lysine-type peptidoglycan in insects. Proc Natl Acad Sci U S A 2007; 104:6602-7. [PMID: 17409189 PMCID: PMC1871832 DOI: 10.1073/pnas.0610924104] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recognition of lysine-type peptidoglycan by peptidoglycan recognition protein (PGRP)-SA provokes the activation of the Toll and prophenoloxidase pathways. Here we reveal that a soluble fragment of lysine-type peptidoglycan, a long glycan chain with short stem peptides, is a potent activator of the Drosophila Toll pathway and the prophenoloxidase activation cascade in the beetle Tenebrio molitor. Using this peptidoglycan fragment, we present biochemical evidence that clustering of PGRP-SA molecules on the peptidoglycan is required for the activation of the prophenoloxidase cascade. We subsequently highlight that the lysozyme-mediated partial digestion of highly cross-linked lysine-type peptidoglycan dramatically increases the binding of PGRP-SA, presumably by inducing clustering of PGRP-SA, which then recruits the Gram-negative bacteria-binding protein 1 homologue and a modular serine protease containing low-density lipoprotein and complement control protein domains. The crucial role of lysozyme in the prophenoloxidase activation cascade is further confirmed in vivo by using a lysozyme inhibitor. Taken together, we propose a model whereby lysozyme presents a processed form of lysine-type peptidoglycan for clustering of PGRP-SA that recruits Gram-negative bacteria-binding protein 1 and the modular serine protease, which leads to the activation of both the Toll and prophenoloxidase pathways.
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Affiliation(s)
- Ji-Won Park
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Chan-Hee Kim
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Jung-Hyun Kim
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Byung-Rok Je
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Kyung-Baeg Roh
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Su-Jin Kim
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Hyeon-Hwa Lee
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Ji-Hwan Ryu
- Division of Molecular Life Science, Ewha Woman's University, Seoul 120-750, Korea; and
| | - Jae-Hong Lim
- Division of Molecular and Life Sciences, Department of Life Sciences, Center for Biomolecular Recognition, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Korea
| | - Byung-Ha Oh
- Division of Molecular and Life Sciences, Department of Life Sciences, Center for Biomolecular Recognition, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Korea
| | - Won-Jae Lee
- Division of Molecular Life Science, Ewha Woman's University, Seoul 120-750, Korea; and
| | - Nam-Chul Ha
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
| | - Bok-Luel Lee
- *National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan 609-735, Korea
- To whom correspondence should be addressed. E-mail:
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Park JW, Je BR, Piao S, Inamura S, Fujimoto Y, Fukase K, Kusumoto S, Söderhäll K, Ha NC, Lee BL. A synthetic peptidoglycan fragment as a competitive inhibitor of the melanization cascade. J Biol Chem 2006; 281:7747-55. [PMID: 16421099 DOI: 10.1074/jbc.m510058200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Melanin synthesis is essential for defense and development but must be tightly controlled because systemic hyperactivation of the prophenoloxidase and excessive melanin synthesis are deleterious to the hosts. The melanization cascade of the arthropods can be activated by bacterial lysine-peptidoglycan (PGN), diaminopimelic acid (DAP)-PGN, or fungal beta-1,3-glucan. The molecular mechanism of how DAP- or Lys-PGN induces melanin synthesis and which molecules are involved in distinguishing these PGNs are not known. The identification of PGN derivatives that can work as inhibitors of the melanization cascade and the characterization of PGN recognition molecules will provide important information to clarify how the melanization is regulated and controlled. Here, we report that a novel synthetic Lys-PGN fragment ((GlcNAc-MurNAc-L-Ala-D-isoGln-L-Lys-D-Ala)2, T-4P2) functions as a competitive inhibitor of the natural PGN-induced melanization reaction. By using a T-4P2-coupled column, we purified the Tenebrio molitor PGN recognition protein (Tm-PGRP) without causing activation of the prophenoloxidase. The purified Tm-PGRP recognized both Lys- and DAP-PGN. In vitro reconstitution experiments showed that Tm-PGRP functions as a common recognition molecule of Lys- and DAP-PGN-dependent melanization cascades.
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Affiliation(s)
- Ji Won Park
- National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Kumjeong Ku, Busan 609-735, Korea
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