scholarly journals A revised mechanism for how Plasmodium falciparum recruits and exports proteins into its erythrocytic host cell.

2021 ◽  
Author(s):  
Mikha Gabriela ◽  
Kathryn Matthews ◽  
Cas Boshoven ◽  
Betty Kouskousis ◽  
David Steer ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Host Cell ◽  
Parasitophorous Vacuole ◽  
Specific Interactions ◽  
Parasitophorous Vacuole Membrane ◽  
Conducting Channel ◽  
Trophozoite Stage ◽  
Vacuole Membrane ◽  
N Terminus ◽  
Exported Protein

Plasmodium falciparum exports ~10% of its proteome into its host erythrocyte to modify the host cell’s physiology. The Plasmodium export element (PEXEL) motif contained within the N-terminus of most exported proteins directs the trafficking of those proteins into the erythrocyte. To reach the host cell, the PEXEL motif of exported proteins are processed by the endoplasmic reticulum (ER) resident aspartyl protease plasmepsin V. Then, following secretion into the parasite-encasing parasitophorous vacuole, the mature exported protein must be unfolded and translocated across the parasitophorous vacuole membrane by the Plasmodium translocon of exported proteins (PTEX). PTEX is a protein-conducting channel consisting of the pore-forming protein EXP2, the protein unfoldase HSP101, and structural component PTEX150. The mechanism of how exported proteins are specifically trafficked from the parasite’s ER following PEXEL cleavage to PTEX complexes on the parasitophorous vacuole membrane is currently not understood. Here, we present evidence that EXP2 and PTEX150 form a stable subcomplex that facilitates HSP101 docking. We also demonstrate that HSP101 localises both within the parasitophorous vacuole and within the parasite’s ER throughout the ring and trophozoite stage of the parasite, coinciding with the timeframe of protein export. Interestingly, we found that HSP101 can form specific interactions with model PEXEL proteins in the parasite ER, irrespective of their PEXEL processing status. Collectively, our data suggest that HSP101 recognises and chaperones PEXEL proteins from the ER to the parasitophorous vacuole and given HSP101’s specificity for the EXP2-PTEX150 subcomplex, this provides a mechanism for how exported proteins are specifically targeted to PTEX for translocation into the erythrocyte.

scholarly journals Origins of the parasitophorous vacuole membrane of the malaria parasite, Plasmodium falciparum, in human red blood cells

1992 ◽  
Vol 102 (3) ◽  
pp. 527-532 ◽  
Author(s):  
A.R. Dluzewski ◽  
G.H. Mitchell ◽  
P.R. Fryer ◽  
S. Griffiths ◽  
R.J. Wilson ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cell Membrane ◽  
Host Cell ◽  
Malaria Parasite ◽  
Parasitophorous Vacuole ◽  
Parasitophorous Vacuole Membrane ◽  
Host Cell Membrane ◽  
Vacuole Membrane ◽  
Parasite Plasmodium ◽  
Parasite Plasmodium Falciparum

We have attempted to determine whether the parasitophorous vacuole membrane, in which the malaria parasite (merozoite) encapsulates itself when it enters a red blood cell, is derived from the host cell plasma membrane, as the appearance of the invasion process in the electron microscope has been taken to suggest, or from lipid material stored in the merozoite. We have incorporated into the red cell membrane a haptenic phospholipid, phosphatidylethanolamine, containing an NBD (N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)) group, substituted in the acyl chain, and allowed it to translocate into the inner bilayer leaflet. After invasion of these labelled cells by the parasite, Plasmodium falciparum, immuno-gold electron microscopy was used to follow the distribution of the labelled lipid; this was found to be overwhelmingly in favour of the host cell membrane relative to the parasitophorous vacuole. Merozoites of P. knowlesi were allowed to attach irreversibly to red cells without invasion, using the method of pretreatment with cytochalasin. The region of contact between the merozoite and the host cell membrane was in all cases devoid of the labelled phosphatidylethanolamine. These results lead us to infer that the parasitophorous vacuole membrane is derived wholly or partly from lipid preexisting in the merozoite.

Association of host cell endoplasmic reticulum and mitochondria with the Toxoplasma gondii parasitophorous vacuole membrane: a high affinity interaction

1997 ◽  
Vol 110 (17) ◽  
pp. 2117-2128 ◽  
Author(s):  
A.P. Sinai ◽  
P. Webster ◽  
K.A. Joiner
Keyword(s):  
Endoplasmic Reticulum ◽  
Toxoplasma Gondii ◽  
Host Cell ◽  
Parasitophorous Vacuole ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Parasitophorous Vacuole Membrane ◽  
Vacuole Membrane ◽  
Protein Protein Interaction ◽  
High Affinity

The parasitophorous vacuole membrane (PVM) of the obligate intracellular protozoan parasite Toxoplasma gondii forms tight associations with host mitochondria and the endoplasmic reticulum (ER). We have used a combination of morphometric and biochemical approaches to characterize this unique phenomenon, which we term PVM-organelle association. The PVM is separated from associated mitochondria and ER by a mean distance of 12 and 18 nm, respectively. The establishment of PVM-organelle association is dependent on active parasite entry, but does not require parasite viability for its maintenance. Association is not a consequence of spatial constraints imposed on the growing vacuole. Morphometric analysis indicates that the extent of mitochondrial association with the PVM stays constant as the vacuole enlarges, whereas the extent of ER association decreases. Disruption of host cell microtubules partially blocks the establishment but not the maintenance of PVM-mitochondrial association, and has no significant effect on PVM-ER association. PVM-organelle association is maintained following disruption of infected host cells, as assessed by electron microscopy and by sub-cellular fractionation showing co-migration of fixed PVM and organelle markers. Taken together, the data suggest that a high affinity, potentially protein-protein interaction between parasite and organelle components is responsible for PVM-organelle association.

scholarly journals Skeleton-binding protein 1 functions at the parasitophorous vacuole membrane to traffic PfEMP1 to the Plasmodium falciparum–infected erythrocyte surface

Blood ◽  
2006 ◽  
Vol 109 (3) ◽  
pp. 1289-1297 ◽  
Author(s):  
Alexander G. Maier ◽  
Melanie Rug ◽  
Matthew T. O'Neill ◽  
James G. Beeson ◽  
Matthias Marti ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Protein Transport ◽  
Infected Erythrocyte ◽  
Binding Protein ◽  
Parasitophorous Vacuole ◽  
Surface Protein ◽  
Severe Form ◽  
Parasitophorous Vacuole Membrane ◽  
Vacuole Membrane ◽  
Erythrocyte Surface

Abstract A key feature of Plasmodium falciparum, the parasite causing the most severe form of malaria in humans, is its ability to export parasite molecules onto the surface of the erythrocyte. The major virulence factor and variant surface protein PfEMP1 (P falciparum erythrocyte membrane protein 1) acts as a ligand to adhere to endothelial receptors avoiding splenic clearance. Because the erythrocyte is devoid of protein transport machinery, the parasite provides infrastructure for trafficking across membranes it traverses. In this study, we show that the P falciparum skeleton-binding protein 1 (PfSBP1) is required for transport of PfEMP1 to the P falciparum–infected erythrocyte surface. We present evidence that PfSBP1 functions at the parasitophorous vacuole membrane to load PfEMP1 into Maurer clefts during formation of these structures. Furthermore, the major reactivity of antibodies from malaria-exposed multigravid women is directed toward PfEMP1 because this is abolished in the absence of PfSBP1.

The origin of parasitophorous vacuole membrane lipids in malaria-infected erythrocytes

1993 ◽  
Vol 106 (1) ◽  
pp. 237-248 ◽  
Author(s):  
G.E. Ward ◽  
L.H. Miller ◽  
J.A. Dvorak
Keyword(s):  
Host Cell ◽  
Erythrocyte Membrane ◽  
Membrane Lipids ◽  
Parasitophorous Vacuole ◽  
Light Level ◽  
Surface Proteins ◽  
Parasitophorous Vacuole Membrane ◽  
Host Cell Membrane ◽  
Vacuole Membrane ◽  
Erythrocyte Surface

During invasion of an erythrocyte by a malaria merozoite, an indentation develops in the erythrocyte surface at the point of contact between the two cells. This indentation deepens as invasion progresses, until the merozoite is completely surrounded by a membrane known as the parasitophorous vacuole membrane (PVM). We incorporated fluorescent lipophilic probes and phospholipid analogs into the erythrocyte membrane, and followed the fate of these probes during PVM formation with low-light-level video fluorescence microscopy. The concentration of probe in the forming PVM was indistinguishable from the concentration of probe in the erythrocyte membrane, suggesting that the lipids of the PVM are continuous with and derived from the host cell membrane during invasion. In contrast, fluorescently labeled erythrocyte surface proteins were largely excluded from the forming PVM. These data are consistent with a model for PVM formation in which the merozoite induces a localized invagination in the erythrocyte lipid bilayer, concomitant with a localized restructuring of the host cell cytoskeleton.

scholarly journals Rab5b-Associated Arf1 GTPase Regulates Export of N-Myristoylated Adenylate Kinase 2 From the Endoplasmic Reticulum in Plasmodium falciparum

2021 ◽  
Vol 10 ◽  
Author(s):  
Izumi Taku ◽  
Tomohiro Hirai ◽  
Takashi Makiuchi ◽  
Naoaki Shinzawa ◽  
Shiroh Iwanaga ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasmodium Falciparum ◽  
Membrane Trafficking ◽  
Adenylate Kinase ◽  
Parasitophorous Vacuole ◽  
Super Resolution ◽  
Immunofluorescence Assay ◽  
Rab Gtpases ◽  
Parasitophorous Vacuole Membrane ◽  
Vacuole Membrane

Plasmodium falciparum extensively remodels human erythrocytes by exporting hundreds of parasite proteins. This remodeling is closely linked to the Plasmodium virulence-related functions and immune evasion. The N-terminal export signal named PEXEL (Plasmodium export element) was identified to be important for the export of proteins beyond the PVM, however, the issue of how these PEXEL-positive proteins are transported and regulated by Rab GTPases from the endoplasmic reticulum (ER) to the cell surface has remained poorly understood. Previously, we identified new aspects of the trafficking of N-myristoylated adenylate kinase 2 (PfAK2), which lacks the PEXEL motif and is regulated by the PfRab5b GTPase. Overexpression of PfRab5b suppressed the transport of PfAK2 to the parasitophorous vacuole membrane and PfAK2 was accumulated in the punctate compartment within the parasite. Here, we report the identification of PfRab5b associated proteins and dissect the pathway regulated by PfRab5b. We isolated two membrane trafficking GTPases PfArf1 and PfRab1b by coimmunoprecipitation with PfRab5b and via mass analysis. PfArf1 and PfRab1b are both colocalized with PfRab5b adjacent to the ER in the early erythrocytic stage. A super-resolution microgram of the indirect immunofluorescence assay using PfArf1 or PfRab1b- expressing parasites revealed that PfArf1 and PfRab1b are localized to different ER subdomains. We used a genetic approach to expresses an active or inactive mutant of PfArf1 that specifically inhibited the trafficking of PfAK2 to the parasitophorous vacuole membrane. While expression of PfRab1b mutants did not affect in the PfAK2 transport. In contrast, the export of the PEXEL-positive protein Rifin was decreased by the expression of the inactive mutant of PfRab1b or PfArf1. These data indicate that the transport of PfAK2 and Rifin were recognized at the different ER subdomain by the two independent GTPases: PfAK2 is sorted by PfArf1 into the pathway for the PV, and the export of Rifin might be sequentially regulated by PfArf1 and PfRab1b.

scholarly journals Exp2 in the Role of the Small Molecule Pore in the Parasitophorous Vacuole Membrane of Plasmodium falciparum

2018 ◽  
Vol 114 (3) ◽  
pp. 492a ◽  
Author(s):  
Matthias Garten ◽  
Josh R. Beck ◽  
Svetlana Glushakova ◽  
Armiyaw S. Nasamu ◽  
Jacquin C. Niles ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Small Molecule ◽  
Parasitophorous Vacuole ◽  
Parasitophorous Vacuole Membrane ◽  
Vacuole Membrane

scholarly journals Genesis of and Trafficking to the Maurer's Clefts of Plasmodium falciparum-Infected Erythrocytes

2006 ◽  
Vol 26 (11) ◽  
pp. 4074-4085 ◽  
Author(s):  
Cornelia Spycher ◽  
Melanie Rug ◽  
Nectarios Klonis ◽  
David J. P. Ferguson ◽  
Alan F. Cowman ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Fluorescent Protein ◽  
Transmembrane Domain ◽  
Imaging Techniques ◽  
Parasitophorous Vacuole ◽  
Time Lapse ◽  
Cell Periphery ◽  
Parasitophorous Vacuole Membrane ◽  
Vacuole Membrane ◽  
Maurer's Clefts

ABSTRACT Malaria parasites export proteins beyond their own plasma membrane to locations in the red blood cells in which they reside. Maurer's clefts are parasite-derived structures within the host cell cytoplasm that are thought to function as a sorting compartment between the parasite and the erythrocyte membrane. However, the genesis of this compartment and the signals directing proteins to the Maurer's clefts are not known. We have generated Plasmodium falciparum-infected erythrocytes expressing green fluorescent protein (GFP) chimeras of a Maurer's cleft resident protein, the membrane-associated histidine-rich protein 1 (MAHRP1). Chimeras of full-length MAHRP1 or fragments containing part of the N-terminal domain and the transmembrane domain are successfully delivered to Maurer's clefts. Other fragments remain trapped within the parasite. Fluorescence photobleaching and time-lapse imaging techniques indicate that MAHRP1-GFP is initially trafficked to isolated subdomains in the parasitophorous vacuole membrane that appear to represent nascent Maurer's clefts. The data suggest that the Maurer's clefts bud from the parasitophorous vacuole membrane and diffuse within the erythrocyte cytoplasm before taking up residence at the cell periphery.

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