Sequence- and structure-based bioinformatic screening for potential Theileria parva transport-related proteins

As an obligate intracellular parasite, Theileria parva is strictly dependent on its host for nutrient acquisition. Transport proteins are expected to play a crucial role in the influx of essential nutrients to sustain the parasite's rapid growth. Unfortunately, the T. parva transportome is still not comprehensively elucidated, and plagued by the presence of uncharacterized proteins. In this study, we employed a combination of approaches including sequence orthology and structural similarity to identify 188 proteins predicted to be involved in transport-related processes. Among these, 24 were uncharacterized proteins, and 17 of them could be assigned a tentative annotation. Furthermore, the localization of these 188 proteins was investigated, resulting in their assignment to seven cellular compartments. Screening of the proteomes of other Theileria species, T. annulata, T. orientalis, and T. equi revealed that all 188 proteins were present in both transforming and non-transforming Theileria parasites. Among the 188 potential transport-related proteins, 45 were associated with transmembrane transport and most of them (87 %) are conserved across phylum Apicomplexa.