Schematic of TLR4 signaling cascades. Activation of TLR4 signal transduction through MyD88/TIRAP and TRAM/TRIF pathways leads to activation of innate immune responses and inhibition of insulin signal transduction, primarily through IRS serine phosphorylation. Additional cellular responses to TLR4 activation not shown include activation of NADPH oxidase, cytoskeletal rearrangement, and internalization of TLR4 complexes to endosomal compartments.
