Identification, organization, and record of rhomboid proteases of Babesia and Theileria hemoprotozoans

POKLEPOVICH,TOMAS; GALLENTI, ROMINA; FLORIN-CHRISTENSEN, M; SCHNITTGER, LEONHARD

Congreso; Congreso de biología Computacional: ISCB Latin America Bioinformatics conference; 2016

Background: Rhomboidproteases constitute a large family of integral membrane proteins, designatedas family S54 of serine peptidases. Their active sites are formed by acatalytic dyad (S, H) immersed in the lipid bilayer. In protozoa of the phylumApicomplexa, it has been shown that rhomboid proteasescleave certain surface proteins facilitating the entry of parasites into thehost cells. The aim of this study was to identify, organize, and record therepertoire of rhomboid peptidases in the parasites that belong to the genera Babesia and Theileria and whose genomes have been sequenced.Results: In the seven investigated species 39 proteinase sequences wereidentified, of which 24 are functional: 3 in the genomes of T. annulata, T. parva, and T. orientalis, respectively, 1 in T. equi, 7 en Babesia bovis, 4in B. bigemina and 3 in B. microti. All rhomboids could be assignedto the subfamilies ROM4/5, ROM6, ROM7, ROM8, and ROM9 suggesting that ROM1, ROM2,ROM3, and ROM10 subfamilies are absent in these parasite genera. Interestingly,the ROM6 proteinases were found to be orthologous between all studied Theileriaand Babesia species. Furthermore, in the genome of B. bovis a gene coding for ROM4/5 has expanded to a familyconsisting of three tandemly arranged paralogs.Conclusions: Of the 39 sequences identified as ROM peptidases, 28 havenot been described yet. Of particular interest are ROM4/5 proteinases sincetheir inclusion into a  subunit vaccinehas been shown to protect against infection by the apicomplexan Eimeria tenella. Supportedby INTA PNBIO 1131034 and PICT 2013-1249.