Signal transduction by BG. BG activate immune and non-immune cells through TLR2 and TLR4 pathways, culminating in the production of a variety of proinflammatory cytokines, chemokines, and host defence genes via MyD88 and MyD88 independent signaling pathways. Signaling through TLR2 or TLR4 is the MyD88 dependent adapter molecule that passes the signal to MAPK and IkB cascades. These signaling cascades result in the production of NF-kB and AP-1 transcription factors which subsequently induce a variety of genes involved in innate and adaptive immunity. Signaling through TLR4 is also MyD88 independent and occurs via IRF3 pathway, which results in the production of NO and anti-viral cytokines including interferon-α and interferon-β.