Members of the Toll-like receptor (TLR) family, named for the closely related Toll receptor inDrosophila, play a pivotal role in innate immune responses. TLRs recognize conserved motifs found in various pathogens and mediate defense responses. Toll-like receptor 2 (TLR2) is expressed on the surface of monocytes and macrophages and can heterodimerize with TLR1 or TLR6, enabling responses to a variety of pathogen-associated molecular signals including lipopeptides and peptidoglycan. TLR6 is highly homologous to TLR1, sharing greater than 65% sequence identity, and, like other members of TLR family, it induces NFkB signaling upon activation.
