Proteolytic Cleavage in an Endolysosomal Compartment is Required for Activation of Toll-like Receptor 9

Overview

Journal Nat Immunol

Date 2008 Oct 22

PMID 18931679

Citations 240

Authors

Boyoun Park

Melanie M Brinkmann

Eric Spooner

Clarissa C Lee

You-Me Kim

Hidde L Ploegh

Affiliations

Soon will be listed here.

Abstract

Toll-like receptors (TLRs) activate the innate immune system in response to pathogens. Here we show that TLR9 proteolytic cleavage is a prerequisite for TLR9 signaling. Inhibition of lysosomal proteolysis rendered TLR9 inactive. The carboxy-terminal fragment of TLR9 thus generated included a portion of the TLR9 ectodomain, as well as the transmembrane and cytoplasmic domains. This cleavage fragment bound to the TLR9 ligand CpG DNA and, when expressed in Tlr9(-/-) dendritic cells, restored CpG DNA-induced cytokine production. Although cathepsin L generated the requisite TLR9 cleavage products in a cell-free in vitro system, several proteases influenced TLR9 cleavage in intact cells. Lysosomal proteolysis thus contributes to innate immunity by facilitating specific cleavage of TLR9.

Citing Articles

The Inhibitory Effects of Alpha 1 Antitrypsin on Endosomal TLR Signaling Pathways.

Elshikha A, Abboud G, Avdiaj R, Morel L, Song S Biomolecules. 2025; 15(1).

PMID: 39858436 PMC: 11763108. DOI: 10.3390/biom15010043.

A central role of stimulator of interferon genes' adaptor protein in defensive immune response.

Kaushal A Immunol Res. 2025; 73(1):39.

PMID: 39836303 DOI: 10.1007/s12026-024-09587-1.

Endolysosomal transient receptor potential mucolipins and two-pore channels: implications for cancer immunity.

Ouologuem L, Bartel K Front Immunol. 2024; 15:1389194.

PMID: 38840905 PMC: 11150529. DOI: 10.3389/fimmu.2024.1389194.

Large-scale mutational analysis identifies UNC93B1 variants that drive TLR-mediated autoimmunity in mice and humans.

Rael V, Yano J, Huizar J, Slayden L, Weiss M, Turcotte E J Exp Med. 2024; 221(8).

PMID: 38780621 PMC: 11116816. DOI: 10.1084/jem.20232005.

Mitochondrial DNA Sensing Pathogen Recognition Receptors in Systemic Sclerosis Associated Interstitial Lung Disease: A Review.

Ghincea A, Woo S, Yu S, Pivarnik T, Fiorini V, Herzog E Curr Treatm Opt Rheumatol. 2024; 9(4):204-220.

PMID: 38230363 PMC: 10791121. DOI: 10.1007/s40674-023-00211-1.

References

Takeuchi O, Hoshino K, Kawai T, Sanjo H, Takada H, Ogawa T . Differential roles of TLR2 and TLR4 in recognition of gram-negative and gram-positive bacterial cell wall components. Immunity. 1999; 11(4):443-51. DOI: 10.1016/s1074-7613(00)80119-3. View

Brinkmann M, Spooner E, Hoebe K, Beutler B, Ploegh H, Kim Y . The interaction between the ER membrane protein UNC93B and TLR3, 7, and 9 is crucial for TLR signaling. J Cell Biol. 2007; 177(2):265-75. PMC: 2064135. DOI: 10.1083/jcb.200612056. View

Villadangos J, Ploegh H . Proteolysis in MHC class II antigen presentation: who's in charge?. Immunity. 2001; 12(3):233-9. DOI: 10.1016/s1074-7613(00)80176-4. View

Ozinsky A, Underhill D, Fontenot J, Hajjar A, Smith K, Wilson C . The repertoire for pattern recognition of pathogens by the innate immune system is defined by cooperation between toll-like receptors. Proc Natl Acad Sci U S A. 2000; 97(25):13766-71. PMC: 17650. DOI: 10.1073/pnas.250476497. View

Hemmi H, Takeuchi O, Kawai T, Kaisho T, Sato S, Sanjo H . A Toll-like receptor recognizes bacterial DNA. Nature. 2000; 408(6813):740-5. DOI: 10.1038/35047123. View

Hayashi F, Smith K, Ozinsky A, Hawn T, Yi E, Goodlett D . The innate immune response to bacterial flagellin is mediated by Toll-like receptor 5. Nature. 2001; 410(6832):1099-103. DOI: 10.1038/35074106. View

Takeuchi O, Kawai T, Muhlradt P, Morr M, Radolf J, Zychlinsky A . Discrimination of bacterial lipoproteins by Toll-like receptor 6. Int Immunol. 2001; 13(7):933-40. DOI: 10.1093/intimm/13.7.933. View

Kawai T, Takeuchi O, Fujita T, Inoue J, Muhlradt P, Sato S . Lipopolysaccharide stimulates the MyD88-independent pathway and results in activation of IFN-regulatory factor 3 and the expression of a subset of lipopolysaccharide-inducible genes. J Immunol. 2001; 167(10):5887-94. DOI: 10.4049/jimmunol.167.10.5887. View

Lennon-Dumenil A, Bakker A, Ploegh H, Lagaudriere-Gesbert C . A closer look at proteolysis and MHC-class-II-restricted antigen presentation. Curr Opin Immunol. 2002; 14(1):15-21. DOI: 10.1016/s0952-7915(01)00293-x. View

10.

Hemmi H, Kaisho T, Takeuchi O, Sato S, Sanjo H, Hoshino K . Small anti-viral compounds activate immune cells via the TLR7 MyD88-dependent signaling pathway. Nat Immunol. 2002; 3(2):196-200. DOI: 10.1038/ni758. View

11.

Janeway Jr C, Medzhitov R . Innate immune recognition. Annu Rev Immunol. 2002; 20:197-216. DOI: 10.1146/annurev.immunol.20.083001.084359. View

12.

Felbor U, Kessler B, Mothes W, Goebel H, Ploegh H, Bronson R . Neuronal loss and brain atrophy in mice lacking cathepsins B and L. Proc Natl Acad Sci U S A. 2002; 99(12):7883-8. PMC: 122989. DOI: 10.1073/pnas.112632299. View

13.

Greenbaum D, Arnold W, Lu F, Hayrapetian L, Baruch A, Krumrine J . Small molecule affinity fingerprinting. A tool for enzyme family subclassification, target identification, and inhibitor design. Chem Biol. 2002; 9(10):1085-94. DOI: 10.1016/s1074-5521(02)00238-7. View

14.

Takeda K, Kaisho T, Akira S . Toll-like receptors. Annu Rev Immunol. 2003; 21:335-76. DOI: 10.1146/annurev.immunol.21.120601.141126. View

15.

Latz E, Schoenemeyer A, Visintin A, Fitzgerald K, Monks B, Knetter C . TLR9 signals after translocating from the ER to CpG DNA in the lysosome. Nat Immunol. 2004; 5(2):190-8. DOI: 10.1038/ni1028. View

16.

Diebold S, Kaisho T, Hemmi H, Akira S, Reis e Sousa C . Innate antiviral responses by means of TLR7-mediated recognition of single-stranded RNA. Science. 2004; 303(5663):1529-31. DOI: 10.1126/science.1093616. View

17.

Heil F, Hemmi H, Hochrein H, Ampenberger F, Kirschning C, Akira S . Species-specific recognition of single-stranded RNA via toll-like receptor 7 and 8. Science. 2004; 303(5663):1526-9. DOI: 10.1126/science.1093620. View

18.

Leifer C, Kennedy M, Mazzoni A, Lee C, Kruhlak M, Segal D . TLR9 is localized in the endoplasmic reticulum prior to stimulation. J Immunol. 2004; 173(2):1179-83. PMC: 2757936. DOI: 10.4049/jimmunol.173.2.1179. View

19.

Wright S, Ramos R, Tobias P, Ulevitch R, Mathison J . CD14, a receptor for complexes of lipopolysaccharide (LPS) and LPS binding protein. Science. 1990; 249(4975):1431-3. DOI: 10.1126/science.1698311. View

20.

Kominami E, Ueno T, Muno D, Katunuma N . The selective role of cathepsins B and D in the lysosomal degradation of endogenous and exogenous proteins. FEBS Lett. 1991; 287(1-2):189-92. DOI: 10.1016/0014-5793(91)80048-8. View