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. Author manuscript; available in PMC: 2013 Dec 7.
Published in final edited form as: Cell. 2012 Dec 7;151(6):1168–1178. doi: 10.1016/j.cell.2012.11.011

Figure 2. Signaling organelles of the innate immune system.

Figure 2

Illustrated is a typical mammalian macrophage that harbors innate immune receptors in specific subcellular locations. The subcellular sites indicated are the sites of receptor residence after microbe-induced receptor transport. The legend indicates the type of signaling pathway activated from each location. Note in most cases, the sites of receptor signaling differ from the sites of microbial detection, as illustrated in Figure 1. At the plasma membrane rafts are bacterial sensing TLRs such as TLRs 1, 2, 4, 5, and 6. Within early endosomes is TLR4. The virus sensing TLRs 3, 7, 8, 9 and 13 may signal from late endosomes and lysosomes-related organelles, although this has been only formally demonstrated for TLR9. The RLRs RIG-I and MDA5 signal from mitochondria and peroxisomes that are docked at the MAM. Note, that some of the receptors indicated in Figure 1 are not illustrated here, because not enough information is available to define their sites of signaling.