MyD88-dependent and MyD88-independent TLR signaling pathways. Most TLRs require MyD88; however, TLR4 can transmit signals by utilizing the alternative adapters, TRAM and TRIF. Like MyD88, this sub-pathway can activate NF-κB, but can regulate transcription of target genes in a manner that may be distinct from that elicited by the classical MyD88-dependent route. HSP65, heat shock protein 65; LAM, lipoarabinomannan; LM, lipomannan; PIMs, phosphatidyl-myoinositol mannosidases; STF, soluble tuberculosis factor; TIRAP, TIR domain–containing adapter protein.