A 95 kDa protein of Plasmodium vivax and P. cynomolgi visualized by three-dimensional tomography in the caveola-vesicle complexes (Schuffner's dots) of infected erythrocytes is a member of the PHIST family

作者：Akinyi Sheila; Hanssen Eric; Meyer Esmeralda V S; Jiang Jianlin; Korir Cindy C; Singh Balwan; Lapp Stacey; Barnwell John W; Tilley Leann; Galinski Mary R^*

来源：Molecular Microbiology, 2012, 84(5): 816-831.

DOI：10.1111/j.1365-2958.2012.08060.x

Plasmodium vivax and P. cynomolgi produce numerous caveolavesicle complex (CVC) structures within the surface of the infected erythrocyte membrane. These contrast with the electron-dense knob protrusions expressed at the surface of Plasmodium falciparum-infected erythrocytes. Here we investigate the three-dimensional (3-D) structure of the CVCs and the identity of a predominantly expressed 95 kDa CVC protein. Liquid chromatography tandem mass spectrometry analysis of immunoprecipitates by monoclonal antibodies from P. cynomolgi extracts identified this protein as a member of the Plasmodium helical interspersed subtelomeric (PHIST) superfamily with a calculated mass of 81 kDa. We named the orthologous proteins PvPHIST/CVC-8195 and PcyPHIST/CVC-8195, analysed their structural features, including a PEXEL motif, repeated sequences and a C-terminal PHIST domain, and show that PHIST/CVC-8195 is most highly expressed in trophozoites. We generated images of CVCs in 3-D using electron tomography (ET), and used immuno-ET to show PHIST/CVC-8195 localizes to the cytoplasmic side of the CVC tubular extensions. Targeted gene disruptions were attempted in vivo. The pcyphist/cvc-8195 gene was not disrupted, but parasites containing episomes with the tgdhfr selection cassette were retrieved by selection with pyrimethamine. This suggests that PHIST/CVC-8195 is essential for survival of these malaria parasites.

• 出版日期2012-6