Mycobacterium tuberculosis lipoprotein-induced association of TLR2 with protein kinase C zeta in lipid rafts contributes to reactive oxygen species-dependent inflammatory signalling in macrophages.
Membrane lipid rafts are enriched in cholesterol and play an important role as signalling platforms. However, the roles of lipid rafts and associated signalling molecules in the innate immune responses to mycobacteria remain unknown. Here we show that stimulation with Mycobacterium tuberculosis 19 kDa lipoprotein, a TLR2/1 agonist, results in translocation of TLR2 to lipid rafts, coalescence of lipid rafts and production of reactive oxygen species (ROS) that drive pro-inflammatory responses. Disruption of lipid raft organization markedly reduced lipoprotein-induced ROS and inflammatory responses. Remarkably, the atypical protein kinase C (PKC) zeta was specifically recruited into detergent-resistant membrane fractions and associated with TLR2. PKCzeta activity was critical for lipoprotein-dependent ROS generation, raft coalescence and the pro-inflammatory responses by macrophages. Moreover, lipid raft organization was required for 19 kDa mediated PKCzeta activation. These results demonstrate that TLR2 trafficking and raft coalescence play an essential role for the initiation of lipoprotein-induced innate immune responses via TLR2 and ROS signalling. In addition, PKCzeta targets to lipid rafts and may act as a critical adaptor molecule to regulate lipid raft dynamics during TLR2 signalling.
Shin
Dong-Min
DM
Department of Microbiology, College of Medicine, Chungnam National University, Daejeon 301-747, Korea.
Yang
Chul-Su
CS
Lee
Ji-Yeon
JY
Lee
Sung Joong
SJ
Choi
Hong-Hee
HH
Lee
Hye-Mi
HM
Yuk
Jae-Min
JM
Harding
Clifford V
CV
Jo
Eun-Kyeong
EK
D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology* / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology; D007113:Immunity, Innate; D007249:Inflammation / Q000276:immunology; D008074:Lipoproteins / Q000276:immunology* / Q000494:pharmacology; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D021381:Protein Transport; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000819:agonists / Q000378:metabolism*; D014376:Tuberculosis / Q000276:immunology* / Q000378:metabolism; D047392:beta-Cyclodextrins / Q000494:pharmacology; D000099221:Protein Kinase C zeta
D001426:Bacterial Proteins; D016207:Cytokines; D008074:Lipoproteins; D011493:Protein Kinase C; D017382:Reactive Oxygen Species; D051195:Toll-Like Receptor 2; D047392:beta-Cyclodextrins; D000099221:Protein Kinase C zeta; C087864:19 kDa antigen, Mycobacterium; C108732:methyl-beta-cyclodextrin