title: Schizonts of Theileria annulata interact with the microtubuli network of their host cell via the membrane protein TaSP.
abstract: Intracellular leukoproliferative Theileria are unique as eukaryotic organisms that transform the immune cells of their ruminant host. Theileria utilize the uncontrolled proliferation for rapid multiplication and distribution into host daughter cells. The parasite distribution into the daughter cells is accompanied by a tight association with the host cell mitotic apparatus. Since the molecular basis for this interaction is largely unknown, we investigated the possible involvement of the immunodominant Theileria annulata surface protein, TaSP, in the attachment of the parasite to host cell microtubule network. Confocal microscopic analyses showed co-localization of the TaSP protein with alpha-tubulin and reciprocal immuno-co-precipitation experiments demonstrated an association of TaSP with alpha-tubulin in vivo. In addition, the partially expressed predicted extracellular domain of TaSP co-localized with the mitotic spindle of dividing cells and was co-immunoprecipitated with alpha-tubulin in transiently transfected Cos-7 cells devoid of other T. annulata expressed proteins. Pull-down studies showed that there is a direct interaction between TaSP and polymerized microtubules. Analysis of the interaction of TaSP and host microtubulin during host cell mitosis indicated that TaSP co-localizes and interacts with the spindle poles, the mitotic spindle apparatus and the mid-body. Moreover, TaSP was demonstrated to be localized to the microtubule organizing center and to physically interact with gamma-tubulin. These data support the notion that the TaSP-microtubule interaction may be playing a potential role in parasite distribution into daughter host cells and give rise to the speculation that TaSP may be involved in regulation of microtubule assembly in the host cell.
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Immunology and Cell Biology, Research Center Borstel, Parkallee 22, 23845, Borstel, Germany, useitzer@fz-borstel.de
authors.forename: Ulrike
authors.initials: U
authors.lastname: Seitzer
authors.forename: Silke
authors.initials: S
authors.lastname: Gerber
authors.forename: Doreen
authors.initials: D
authors.lastname: Beyer
authors.forename: Jessica
authors.initials: J
authors.lastname: Dobschanski
authors.forename: Birgit
authors.initials: B
authors.lastname: Kullmann
authors.forename: Daniel
authors.initials: D
authors.lastname: Haller
authors.forename: Jabbar S
authors.initials: JS
authors.lastname: Ahmed
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D015800:Protozoan Proteins / Q000378:metabolism*; D052939:Schizonts / Q000502:physiology*; D008941:Spindle Apparatus / Q000378:metabolism / Q000469:parasitology; D016796:Theileria annulata / Q000472:pathogenicity*; D014404:Tubulin / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D015800:Protozoan Proteins; C456259:TaSP protein, Theileria annulata; D014404:Tubulin