Expression and characterization of the Plasmodium translocon of the exported proteins component EXP2

Hakamada, Kazuaki; Watanabe, Hirokazu; Kawano, Ryuji; Noguchi, Keiichi; Yohda, Masafumi

doi:10.1016/j.bbrc.2016.11.097

Cited by 22 publications

(18 citation statements)

References 24 publications

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“…EXP2, despite lacking a transmembrane domain, has been touted as the most likely PTEX candidate to play this role as it is the component most resistant to carbonate extraction and modeling of this protein suggested it likely forms a pore similar to that of Hemolysin E (HlyE) in Escherichia coli . This was supported by a recent study demonstrating that recombinant EXP2 expressed in E. coli can form pores estimated to comprise of ~ 10–12 EXP2 subunits in lipid bilayers . Previous studies have shown that exported proteins must be unfolded for successful translocation across the PVM , and that protein export is an ATP‐dependent process .…”

Section: Introductionmentioning

confidence: 94%

The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host–parasite interface

et al. 2018

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The pathogenic nature of malaria infections is due in part to the export of hundreds of effector proteins that actively remodel the host erythrocyte. The Plasmodium translocon of exported proteins (PTEX) has been shown to facilitate the trafficking of proteins into the host cell, a process that is essential for the survival of the parasite. The role of the auxiliary PTEX component PTEX88 remains unclear, as previous attempts to elucidate its function through reverse genetic approaches showed that in contrast to the core components PTEX150 and HSP101, knockdown of PTEX88 did not give rise to an export phenotype. Here, we have used biochemical approaches to understand how PTEX88 assembles within the translocation machinery. Proteomic analysis of the PTEX88 interactome showed that PTEX88 interacts closely with HSP101 but has a weaker affinity with the other core constituents of PTEX. PTEX88 was also found to associate with other PV-resident proteins, including chaperones and members of the exported protein-interacting complex that interacts with the major virulence factor PfEMP1, the latter contributing to cytoadherence and parasite virulence. Despite being expressed for the duration of the blood-stage life cycle, PTEX88 was only discretely observed at the parasitophorous vacuole membrane during ring stages and could not always be detected in the major high molecular weight complex that contains the other core components of PTEX, suggesting that its interaction with the PTEX complex may be dynamic. Together, these data have enabled the generation of an updated model of PTEX that now includes how PTEX88 assembles within the complex.

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Section: Introductionmentioning

confidence: 94%

The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host–parasite interface

et al. 2018

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“…However, PTEX's relative novelty offers few clues to how it functions. EXP2 synthesized in the laboratory can form protein channels in lipid bilayers 9 . However, there have been no reports of fulllength HSP101 or PTEX150 having been successfully synthesized for use in in vitro experiments.…”

Section: Spotlight On Proteins That Aid Malariamentioning

confidence: 99%

Spotlight on proteins that aid malaria

Koning-Ward¹

2018

Nature

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“…The heat‐shock protein HSP101 likely contributes to the unfolding of cargo and supplies energy to the complex through its ATPase function. EXP2 forms oligomers and is associated with the PVM, and is presumed to form a protein translocating pore through the PVM . PTEX150 probably serves a structural role acting to link EXP2 and HSP101.…”

Section: Introductionmentioning

confidence: 99%

“…EXP2 forms oligomers and is associated with the PVM, and is presumed to form a protein translocating pore through the PVM. 13,14 PTEX150 probably serves a structural role acting to link EXP2 and HSP101. All 3 of these proteins are essential for the survival of Plasmodium parasites.…”

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confidence: 99%

Spatial organization of protein export in malaria parasite blood stages

Charnaud

Jonsdottir

Sanders

et al. 2018

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Plasmodium falciparum, which causes malaria, extensively remodels its human host cells, particularly erythrocytes. Remodelling is essential for parasite survival by helping to avoid host immunity and assisting in the uptake of plasma nutrients to fuel rapid growth. Host cell renovation is carried out by hundreds of parasite effector proteins that are exported into the erythrocyte across an enveloping parasitophorous vacuole membrane (PVM). The Plasmodium translocon for exported (PTEX) proteins is thought to span the PVM and provide a channel that unfolds and extrudes proteins across the PVM into the erythrocyte. We show that exported reporter proteins containing mouse dihydrofolate reductase domains that inducibly resist unfolding become trapped at the parasite surface partly colocalizing with PTEX. When cargo is trapped, loop-like extensions appear at the PVM containing both trapped cargo and PTEX protein EXP2, but not additional components HSP101 and PTEX150. Following removal of the block-inducing compound, export of reporter proteins only partly recovers possibly because much of the trapped cargo is spatially segregated in the loop regions away from PTEX. This suggests that parasites have the means to isolate unfoldable cargo proteins from PTEX-containing export zones to avert disruption of protein export that would reduce parasite growth.

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Expression and characterization of the Plasmodium translocon of the exported proteins component EXP2

Cited by 22 publications

References 24 publications

The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host–parasite interface

The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host–parasite interface

Spotlight on proteins that aid malaria

Spatial organization of protein export in malaria parasite blood stages

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