First Author | Shamsul HM | Year | 2010 |
Journal | Immunology | Volume | 130 |
Issue | 2 | Pages | 262-72 |
PubMed ID | 20113368 | Mgi Jnum | J:166415 |
Mgi Id | MGI:4844249 | Doi | 10.1111/j.1365-2567.2009.03232.x |
Citation | Shamsul HM, et al. (2010) The Toll-like receptor 2 (TLR2) ligand FSL-1 is internalized via the clathrin-dependent endocytic pathway triggered by CD14 and CD36 but not by TLR2. Immunology 130(2):262-72 |
abstractText | Little is known of how Toll-like receptor (TLR) ligands are processed after recognition by TLRs. This study was therefore designed to investigate how the TLR2 ligand FSL-1 is processed in macrophages after recognition by TLR2. FSL-1 was internalized into the murine macrophage cell line, RAW264.7. Both chlorpromazine and methyl-beta-cyclodextrin, which inhibit clathrin-dependent endocytosis, reduced FSL-1 uptake by RAW264.7 cells in a dose-dependent manner but nystatin, which inhibits caveolae- and lipid raft-dependent endocytosis, did not. FSL-1 was co-localized with clathrin but not with TLR2 in the cytosol of RAW264.7 cells. These results suggest that internalization of FSL-1 is clathrin dependent. In addition, FSL-1 was internalized by peritoneal macrophages from TLR2-deficient mice. FSL-1 was internalized by human embryonic kidney 293 cells transfected with CD14 or CD36 but not by the non-transfected cells. Also, knockdown of CD14 or CD36 in the transfectants reduced FSL-1 uptake. In this study, we suggest that (i) FSL-1 is internalized into macrophages via a clathrin-dependent endocytic pathway, (ii) the FSL-1 uptake by macrophages occurs irrespective of the presence of TLR2, and (iii) CD14 and CD36 are responsible for the internalization of FSL-1. |