Identity of Ca2+ channel homologues in pathogenic parasites.

Protein accession numbers for homologues are shown. Trp channel homologues were identified by homology with the transmembrane region of at least one class of mammalian Trp channel. Trp channels were then annotated according to the classes of mammalian Trp channel to which the full-length protein showed the greatest sequence similarity in BLASTP searches of the human genome (shown in parentheses for Trp channel homologues). Cav homologues include both human Cav channel and S. cerevisiae Cch1 homologues. The S. mansoni protein labelled XP_002576843/42 is formed by concatenated XP_002576843 and XP_002576842 predicted proteins (whose genomic loci are adjacent). The entire concatamer was confirmed as a single intact protein by its identity with the predicted protein: 29191.m000804.twinscan2 (Wellcome Trust Sanger Institute, UK). The number of predicted transmembrane domains (TMDs) present in homologues is indicated in parentheses. In addition to the Ca2+ channel homologues shown, a homologue of the store-operated Ca2+ influx channel Orai1 was found in S. mansoni: XP_002578837 (with shorter splice variant XP_002578838). Homologues of the very recently identified mitochondrial Ca2+ uniporter [124], [125] were also found in Leishmania and Trypanosoma spp. (eg. XP_822290 of T. brucei), as well as S. mansoni (XP_002569737), but were absent from the other parasites examined (data not shown). PM denotes plasma membrane and NF denotes no homologues found.aIdentified by homology with T. gondii protein XP_002367104;bPossible Cav2B fragment, incomplete sequence available.