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
Latz, Eicke ; Visintin, Alberto ; Lien, Egil ; Fitzgerald, Katherine A ; Monks, Brian G. ; Kurt-Jones, Evelyn A. ; Golenbock, Douglas T. ; Espevik, Terje
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UMass Chan Affiliations
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Keywords
Antigens, 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
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Embargo Expiration Date
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Abstract
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 site