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A 95 kDa protein of Plasmodium vivax and P. cynomolgi visualized by three‐dimensional tomography in the caveola–vesicle complexes (Schüffner's dots) of infected erythrocytes is a member of the PHIST family
Author(s) -
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.
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.08060.x
Subject(s) - biology , plasmodium vivax , apicomplexa , plasmodium falciparum , virology , microbiology and biotechnology , malaria , immunology
Summary Plasmodium vivax and P. cynomolgi produce numerous caveola–vesicle 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‐81 95 and PcyPHIST/CVC‐81 95 , analysed their structural features, including a PEXEL motif, repeated sequences and a C‐terminal PHIST domain, and show that PHIST/CVC‐81 95 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‐81 95 localizes to the cytoplasmic side of the CVC tubular extensions. Targeted gene disruptions were attempted in vivo . The pcyphist/cvc‐81 95 gene was not disrupted, but parasites containing episomes with the tgdhfr selection cassette were retrieved by selection with pyrimethamine. This suggests that PHIST/CVC‐81 95 is essential for survival of these malaria parasites.