A TGF-β receptor type I from Opisthorchis viverrini. Multiple sequence alignment of the ORFs of OvAE22 with homologues from Schistosoma mansoni (SmRK-I – GenBank AF031557), the hydatid tapeworm Echinococcus multilocularis (TR1 – AJ841786) and human (TGF-β receptor type I – L11695) (A). The overlined region denotes the putative serine-threonine kinase active site in SmRK-I . Residues highlighted in red font in OvAE22 are putative sites of serine/threonine phosphorylation. Both SmRK-I and human TGF-β receptor type I sequences shown here are truncated at the N-terminus and SmRK-I is truncated at the C-terminus for comparative purposes with the partial sequence from O. viverrini. Black boxes denote identical residues shared by two or more of the sequences. Grey boxes denote conservative substitutions. Neighbour joining phylogenetic tree showing the relationship between the ORF of OvAE22 and other members of the TGF-β receptor type I family (B). Numbers on branches denote bootstrap values from 100 samplings. The nominated outgroup was the type 2 receptor, SmRK-2. GenBank accession numbers not already provided above are as follows: pig bone morphogenic protein (BMP) receptor type I (AY065994); dog hookworm Ancylostoma caninum S/T kinase (AY053388); Caenorhabditis briggsae CBG02627 (CAAC01000012); filarial nematode Brugia pahangi trk-1 (AF013991); S. mansoni SmRK-2 (AY550912).