Figure 1.

Species homology between the Toll, TLRs, NLRs and plant resistance (R) proteins. Central to innate immunity are the highly conserved core domains that are found in drosophilae, mammals and plants. The Toll family of proteins share homology in their signalling domains with IL-1RI; this family includes Drosophila Toll, plant R proteins, and mammalian TLRs and NLRs. CARD, caspase activation and recruitment; IL-1RI, type I IL-1 receptor; LRR, leucine rich repeat; NALP1, NACHT, leucine rich repeat and pyrin domain containing 1; NLR, NOD-like receptor; PYD, pyrin domain; TLR, Toll-like receptor.