title: Lipopeptides are signaled by Toll-like receptor 1, 2 and 6 in endolysosomes.
abstract: Toll-like receptors (TLRs) recognize a variety of microbial products and induce defense responses. Pathogen sensing by TLRs occurs either on the cell surface or in endolysosomes. TLR-dependent responses are greatly influenced by the site of pathogen sensing. TLR heterodimers TLR1/TLR2 and TLR2/TLR6 recognize tri- or diacylated microbial lipopeptides, respectively. Although TLR1, 2 and 6 are believed to localize on the cell surface of immune cells, little is known about where lipopeptides are signaled. In this study, we established mAbs to TLR1, 2 and 6. TLR1, 2 and 6 were expressed on the surface of B cells, monocytes and dendritic cells in a manner dependent on a TLR-specific chaperone PRAT4A (protein associated with TLR4 A). Cell surface localization of TLR1 or TLR6 was not necessarily required for TLR2 response. Furthermore, a dynamin inhibitor 'Dynasore' abolished the lipopeptide responses by preventing lipopeptide internalization into LAMP-1 and LAMP-2 positive compartments. Our findings suggest that lipopeptides elicit TLR1/2 and TLR2/6 signaling in the endolysosomes, but not on the cell surface.
authors.affiliation: Division of Innate Immunity, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Motoi
authors.affiliation: Division of Innate Immunity, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan Laboratory of Innate Immunity, Center for Experimental Medicine and Systems Biology, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Shibata
authors.affiliation: Division of Hematology, Respiratory Medicine and Oncology, Department of Internal Medicine, Saga University Medical School, 5-1-1 Nabeshima, Sagashi, Saga 849-8501, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Division of Innate Immunity, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Kanno
authors.affiliation: Division of Innate Immunity, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Murakami
authors.affiliation: Division of Innate Immunity, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Biochemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minatoku, Tokyo 105-8512, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kasahara
authors.affiliation: Division of Innate Immunity, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan Laboratory of Innate Immunity, Center for Experimental Medicine and Systems Biology, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan kmiyake@ims.u-tokyo.ac.jp.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Miyake
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001402:B-Lymphocytes / Q000378:metabolism; D001854:Bone Marrow Cells / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003713:Dendritic Cells / Q000378:metabolism; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis / Q000276:immunology; D011992:Endosomes / Q000378:metabolism*; D055666:Lipopeptides / Q000378:metabolism*; D052118:Lysosomal-Associated Membrane Protein 1 / Q000378:metabolism; D052119:Lysosomal-Associated Membrane Protein 2 / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009000:Monocytes / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism; D055503:Protein Multimerization; D021381:Protein Transport; D051381:Rats; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D051194:Toll-Like Receptor 1 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D051216:Toll-Like Receptor 6 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D055666:Lipopeptides; D052118:Lysosomal-Associated Membrane Protein 1; D052119:Lysosomal-Associated Membrane Protein 2; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051216:Toll-Like Receptor 6; D034281:Dynamins
keywords: TLR2; cell surface expression; endolysosome; internalization; lipopeptides