The Drosophila Toll family. (A) Alignment
of the TIR domains from Drosophila Toll-related
molecules and human TLR4, IL-1 receptor type I (IL-1RI), and MyD88.
Sequences were aligned by using the clustal method.
Conserved residues are shaded in black. Residues affected in the
loss-of-function r444, rB1, and
rB2 alleles of Toll are indicated by
arrowheads (46). The black dot points to the position of the Pro
residue critical for TLR4 signaling. (B) Phylogenetic
relationship between Drosophila Toll molecules based on
the alignment shown in A and generated by the
neighbor-joining method. The scale beneath the tree measures the
distance between the sequences. The chromosomal localization of the
Toll-related genes is indicated (Right).
(C) Schematic representation of domain organization of
Drosophila Toll-related molecules and human TLR4. The
receptors are grouped according to conservation of their TIR domains.
The leucine-rich repeats are indicated by small rectangles, whereas
cysteine-rich carboxyl-flanking motifs and cysteine-rich amino-flanking
motifs are represented by half-circles. Black dots indicate
polyglutamine stretches. Incomplete sequences of Toll-3 and Toll-4 are
indicated by dashed lines.