Toll-like receptors (TLRs) have evolved to recognize lipoproteins from diverse species of bacteria. In this issue of Immunity, Kang et al. (2009) provide insight into the mechanisms by which TLR2-TLR6 heterodimers recognize diacylated liporoteins, whereas TLR2-TLR1 heterodimers recognize triacylated lipopeptides.
