Send to

Choose Destination
Nat Immunol. 2004 Feb;5(2):190-8. Epub 2004 Jan 11.

TLR9 signals after translocating from the ER to CpG DNA in the lysosome.

Author information

Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Lazare Research Building 308, 364 Plantation Street, Worcester, MA 01605, USA.


Microbial DNA sequences containing unmethylated CpG dinucleotides activate Toll-like receptor 9 (TLR9). We have found that TLR9 is localized to the endoplasmic reticulum (ER) of dendritic cells (DCs) and macrophages. Because there is no precedent for immune receptor signaling in the ER, we investigated how TLR9 is activated. We show that CpG DNA binds directly to TLR9 in ligand-binding studies. CpG DNA moves into early endosomes and is subsequently transported to a tubular lysosomal compartment. Concurrent with the movement of CpG DNA in cells, TLR9 redistributes from the ER to CpG DNA-containing structures, which also accumulate MyD88. Our data indicate a previously unknown mechanism of cellular activation involving the recruitment of TLR9 from the ER to sites of CpG DNA uptake, where signal transduction is initiated.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Nature Publishing Group
Loading ...
Support Center