Lipopolysaccharide rapidly traffics to and from the Golgi apparatus with the toll-like receptor 4-MD-2-CD14 complex in a process that is distinct from the initiation of signal transduction
Authors
Latz, EickeVisintin, Alberto
Lien, Egil
Fitzgerald, Katherine A.
Monks, Brian G.
Kurt-Jones, Evelyn A.
Golenbock, Douglas T.
Espevik, Terje
UMass Chan Affiliations
Department of Medicine, Division of Infectious Diseases and ImmunologyDocument Type
Journal ArticlePublication Date
2002-09-27Keywords
Adaptor Proteins, Signal TransducingAntigens, CD14
Antigens, Differentiation
Antigens, Surface
Blotting, Western
Brefeldin A
Cell Line
Cell Separation
Dose-Response Relationship, Drug
*Drosophila Proteins
Escherichia coli
Flow Cytometry
Fluorescent Dyes
Genes, Reporter
Golgi Apparatus
Green Fluorescent Proteins
Humans
Lipopolysaccharides
Luciferases
Luminescent Proteins
Lymphocyte Antigen 96
Membrane Glycoproteins
Microscopy, Confocal
Microscopy, Fluorescence
Myeloid Differentiation Factor 88
Plasmids
Precipitin Tests
Protein Binding
Protein Structure, Tertiary
Protein Transport
Receptors, Cell Surface
Receptors, Immunologic
Recombinant Fusion Proteins
*Signal Transduction
Time Factors
Toll-Like Receptor 4
Toll-Like Receptors
Transfection
Immunology and Infectious Disease
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
Mammalian responses to LPS require the expression of Toll-like receptor 4 (TLR4), CD14, and MD-2. We expressed fluorescent TLR4 in cell lines and found that TLR4 densely localized to the surface and the Golgi. Similar distributions were observed in human monocytes. Confocal imaging revealed rapid recycling of TLR4-CD14-MD-2 complexes between the Golgi and the plasma membrane. Fluorescent LPS followed these trafficking pathways in CD14-positive cells. The TLR4- adapter protein, MyD88, translocated to the cell surface upon LPS exposure, and cross-linking of surface TLR4 with antibody induced signaling. Golgi-associated TLR4 expression was disrupted by brefeldin A, yet LPS signaling was preserved. We conclude that LPS signaling may be initiated by surface aggregation of TLR4 and is not dependent upon LPS trafficking to the Golgi.Source
J Biol Chem. 2002 Dec 6;277(49):47834-43. Epub 2002 Sep 24. Link to article on publisher's siteDOI
10.1074/jbc.M207873200Permanent Link to this Item
http://hdl.handle.net/20.500.14038/42372PubMed ID
12324469Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1074/jbc.M207873200
Scopus Count
Collections
Related items
Showing items related by title, author, creator and subject.
-
The role of TNF-receptor family members and other TRAF-dependent receptors in bone resorptionGravallese, Ellen M.; Galson, Deborah L.; Goldring, Steven R.; Auron, Philip E. (2001-02-15)The contribution of osteoclasts to the process of bone loss in inflammatory arthritis has recently been demonstrated. Studies in osteoclast biology have led to the identification of factors responsible for the differentiation and activation of osteoclasts, the most important of which is the receptor activator of NF-kappa B ligand/osteoclast differentiation factor (RANKL/ODF), a tumor necrosis factor (TNF)-like protein. The RANKL/ODF receptor, receptor activator of NF-kappa B (RANK), is a TNF-receptor family member present on both osteoclast precursors and mature osteoclasts. Like other TNF-family receptors and the IL-1 receptor, RANK mediates its signal transduction via TNF receptor-associated factor (TRAF) proteins, suggesting that the signaling pathways activated by RANK and other inflammatory cytokines involved in osteoclast differentiation and activation are interconnected.
-
Mal (MyD88-adapter-like) is required for Toll-like receptor-4 signal transductionFitzgerald, Katherine A.; Palsson-McDermott, Eva M.; Bowie, Andrew G.; Jefferies, Caroline A.; Mansell, Ashley S.; Brady, Gerard; Brint, Elizabeth K.; Dunne, Aisling; Gray, Pearl; Harte, Mary T.; et al. (2001-09-07)The recognition of microbial pathogens by the innate immune system involves Toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns. Different TLRs recognize different pathogen-associated molecular patterns, with TLR-4 mediating the response to lipopolysaccharide from Gram-negative bacteria. All TLRs have a Toll/IL-1 receptor (TIR) domain, which is responsible for signal transduction. MyD88 is one such protein that contains a TIR domain. It acts as an adapter, being involved in TLR-2, TLR-4 and TLR-9 signalling; however, our understanding of how TLR-4 signals is incomplete. Here we describe a protein, Mal (MyD88-adapter-like), which joins MyD88 as a cytoplasmic TIR-domain-containing protein in the human genome. Mal activates NF-kappaB, Jun amino-terminal kinase and extracellular signal-regulated kinase-1 and -2. Mal can form homodimers and can also form heterodimers with MyD88. Activation of NF-kappaB by Mal requires IRAK-2, but not IRAK, whereas MyD88 requires both IRAKs. Mal associates with IRAK-2 by means of its TIR domain. A dominant negative form of Mal inhibits NF-kappaB, which is activated by TLR-4 or lipopolysaccharide, but it does not inhibit NF-kappaB activation by IL-1RI or IL-18R. Mal associates with TLR-4. Mal is therefore an adapter in TLR-4 signal transduction.
-
The interferon regulatory factor, IRF5, is a central mediator of toll-like receptor 7 signalingSchoenemeyer, Annett; Barnes, Betsy J.; Mancl, Margo E.; Latz, Eicke; Goutagny, Nadege; Pitha, Paula M.; Fitzgerald, Katherine A.; Golenbock, Douglas T. (2005-02-08)Interferon regulatory factors (IRFs) are critical components of virus-induced immune activation and type I interferon regulation. IRF3 and IRF7 are activated in response to a variety of viruses or after engagement of Toll-like receptor (TLR) 3 and TLR4 by double-stranded RNA and lipopolysaccharide, respectively. The activation of IRF5, is much more restricted. Here we show that in contrast to IRF3 and IRF7, IRF5 is not a target of the TLR3 signaling pathway but is activated by TLR7 or TLR8 signaling. We also demonstrate that MyD88, interleukin 1 receptor-associated kinase 1, and tumor necrosis factor receptor-associated factor 6 are required for the activation of IRF5 and IRF7 in the TLR7 signaling pathway. Moreover, ectopic expression of IRF5 enabled type I interferon production in response to TLR7 signaling, whereas knockdown of IRF5 by small interfering RNA reduced type I interferon induction in response to the TLR7 ligand, R-848. IRF5 and IRF7, therefore, emerge from these studies as critical mediators of TLR7 signaling.