Deakin University
Browse
kalanon-biosynthesis-2012.pdf (3.38 MB)

Biosynthesis, localization, and macromolecular arrangement of the plasmodium falciparum translocon of exported proteins (PTEX)

Download (3.38 MB)
journal contribution
posted on 2012-03-01, 00:00 authored by H Bullen, S Charnaud, Ming Kalanon, D Riglar, C Dekiwadia, N Kangwanrangsan, M Torii, T Tsuboi, J Baum, S Ralph, A Cowman, Tania De Koning-WardTania De Koning-Ward, B Crabb, P Gilson
To survive within its host erythrocyte, Plasmodium falciparum must export hundreds of proteins across both its parasite plasma membrane and surrounding parasitophorous vacuole membrane, most of which are likely to use a protein complex known as PTEX (Plasmodium translocon of exported proteins). PTEX is a putative protein trafficking machinery responsible for the export of hundreds of proteins across the parasitophorous vacuole membrane and into the human host cell. Five proteins are known to comprise the PTEX complex, and in this study, three of the major stoichiometric components are investigated including HSP101 (a AAA+ ATPase), a protein of no known function termed PTEX150, and the apparent membrane component EXP2. We show that these proteins are synthesized in the preceding schizont stage (PTEX150 and HSP101) or even earlier in the life cycle (EXP2), and before invasion these components reside within the dense granules of invasive merozoites. From these apical organelles, the protein complex is released into the host cell where it resides with little turnover in the parasitophorous vacuole membrane for most of the remainder of the following cell cycle. At this membrane, PTEX is arranged in a stable macromolecular complex of >1230 kDa that includes an ∼600-kDa apparently homo-oligomeric complex of EXP2 that can be separated from the remainder of the PTEX complex using non-ionic detergents. Two different biochemical methods undertaken here suggest that PTEX components associate as EXP2-PTEX150-HSP101, with EXP2 associating with the vacuolar membrane. Collectively, these data support the hypothesis that EXP2 oligomerizes and potentially forms the putative membrane-spanning pore to which the remainder of the PTEX complex is attached.

History

Journal

Journal of biological chemistry

Volume

287

Pagination

7871 - 7884

Location

Bethesda, Md.

Open access

  • Yes

ISSN

0021-9258

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2012, American Society for Biochemistry and Molecular Biology

Usage metrics

    Research Publications

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC