Figure 5

Consensus sequences for the teleost and tetrapod ErbB receptors. The alignment was generated in ClustalX [60]. To minimize errors in amino acid sequence from the DNA sequences used in the analysis, a conserved residue was called conserved if it was in 75% of the sequences. In the alignment, gaps are denoted by a dash (-) and non-conserved residues are indicated by an X. Reverse text (white text on black background) denotes residues that are at least 75% conserved between the different ligands, with grey shaded text (black text on grey background) denoting residues that are different at these conserved positions. The color bars along the top denote different subdomains within the receptor: red, subdomain I; magenta, subdomain II; green, subdomain III; cyan, subdomain IV; yellow, transmembrane; blue, intracellular juxtamembrane domain; and orange, kinase domain. The sequences start at the beginning of the second exon, and the residue numbers are for the human receptors. The regions or residues of interest are: (A) extended regions that are not well conserved in ErbB2 sequences; (B) extracellular juxtamembrane region that is alternatively spliced in ErbB4 yielding a long and short form; (C) the one glycosylation site that is conserved in the four receptors; (D) regions in the kinase domain where ErbB3 differs relative to the other three receptors, corresponding to the C-helix (D1) and the activation loop (D2); (E) the C-terminal portion of the kinase domain that has receptor-specific sequences and has been shown to be involved in mediating high affinity binding; (#) residue involved in subdomain II-subdomain II interactions in the receptor dimer and subdomain II-subdomain IV interactions in the tethered receptor monomer; (&) and (*) residues involved in subdomain II-subdomain II interactions in the receptor dimer; (+) residues involved in subdomain II-subdomain IV interactions in the tethered receptor monomer; and (^) residues that interact with ligand.