JNK-interacting protein 3 associates with Toll-like receptor 4 and is involved in LPS-mediated JNK activation.
Lipopolysaccharide (LPS) is recognized by Toll-like receptor (TLR) 4 and activates NF-kappaB and a set of MAP kinases. Here we have investigated proteins associated with the cytoplasmic domain of mouse TLR4 by yeast two-hybrid screening and identified JNK-interacting protein 3 (JIP3), a scaffold protein for JNK, as a TLR4-associated protein. In mammalian cells, JIP3, through its N-terminal region, constitutively associates with TLR4. The association is specific to JIP3, as the two other JIPs, JIP1 and JIP2, failed to bind TLR4. In HEK 293 cells exogenously expressing TLR4, MD2 and CD14, co-expression of JIP3 significantly increased the complex formation of TLR4-JNK and LPS-mediated JNK activation. In contrast, expression of C-terminally truncated forms of JIP3 impaired LPS-induced JNK activation in a mouse macrophage cell line, RAW264.7. Moreover, RNA interference of JIP3 inhibited LPS-mediated JNK activation. In RAW264.7 cells, JIP3 associates MEKK-1, but not with TAK-1. Finally, JIP3 also associates with TLR2 and TLR9, but not with TLR1 or TLR6. Altogether, our data indicate the involvement of JIP3 in JNK activation in downstream signals of some TLRs.
Matsuguchi
Tetsuya
T
Division of Host Defense, Center for Neural Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan. tmatsugu@med.nagoya-u.ac.jp
Masuda
Akio
A
Sugimoto
Kenji
K
Nagai
Yoshiyuki
Y
Yoshikai
Yasunobu
Y
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides / Q000633:toxicity*; D048728:MAP Kinase Kinase Kinase 1; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014162:Transfection; D020798:Two-Hybrid System Techniques; D000099151:MAP Kinase Kinase Kinase 7
D048868:Adaptor Proteins, Signal Transducing; D018076:DNA, Complementary; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides; D048728:MAP Kinase Kinase Kinase 1; D020930:MAP Kinase Kinase Kinases; D008562:Membrane Glycoproteins; D020928:Mitogen-Activated Protein Kinases; D009419:Nerve Tissue Proteins; D017346:Protein Serine-Threonine Kinases; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D000099151:MAP Kinase Kinase Kinase 7; C403619:Mapk8ip3 protein, mouse; C482578:Map3k1 protein, mouse