The ESCRT-III machinery participates in the production of extracellular vesicles and protein export during Plasmodium falciparum infection

Abstract

Infection with Plasmodium falciparum enhances extracellular vesicle (EV) production in parasitized red blood cells (pRBCs), an important mechanism for parasite-to-parasite communication during the asexual intraerythrocytic life cycle. The endosomal sorting complex required for transport (ESCRT), and in particular the ESCRT-III sub-complex, participates in the formation of EVs in higher eukaryotes. However, RBCs have lost the majority of their organelles through the maturation process, including an important reduction in their vesicular network. Therefore, the mechanism of EV production in P. falciparum-infected RBCs remains to be elucidated. Here we demonstrate that P. falciparum possesses a functional ESCRT-III machinery activated by an alternative recruitment pathway involving the action of PfBro1 and PfVps32/PfVps60 proteins. Additionally, multivesicular body formation and membrane shedding, both reported mechanisms of EVs production, were reconstituted in the membrane model of giant unilamellar vesicles using the purified recombinant proteins. Moreover, the presence of PfVps32, PfVps60 and PfBro1 in EVs purified from a pRBC culture was confirmed by super-resolution microscopy and dot blot assays. Finally, disruption of the Pfvps60 gene led to a reduction in the number of the produced EVs in the KO strain and affected the distribution of other ESCRT-III components. Overall, our results increase the knowledge on the underlying molecular mechanisms during malaria pathogenesis and demonstrate that ESCRT-III P. falciparum proteins participate in EV production.

Toxoplasma gondii exploits the host ESCRT machinery for parasite uptake of host cytosolic proteins

“…However, the extent to which liver stage parasites internalize host protein remains to be determined. Recent work has identified a role for malaria homologs of ESCRT in the generation of extracellular vesicles derived from infected erythrocytes [ 70 ]. This study, however, did not distinguish whether such parasite ESCRT homologs function within the parasite, at the PVM, in cytoplasmic membranous structures, or at the erythrocyte plasma membrane.…”

Vps60 initiates formation of alternative membrane-bound ESCRT-III filaments

“…This notion, is supported by a unique cellular localization of GFP-tagged Vps60 in vivo to not only the endosomal, as it is observed for Snf7, but also yeast’s vacuolar membrane 66,83 . Separated functional pathways were also suggested for ESCRT-III subunits PfVps32 (Snf7 homolog) and PfVps60 during EV-formation in Plasmodium falciparum infected red blood cells 82 . Finally, the author attributed the formation of smaller vesicles to the Vps60-dependent pathway which would agree with the smaller filament structures we observed.…”

“…infected red blood cells suggests that PfVps32 (Snf7 homologue) and PfVps60 function in two parallel pathways during formation of extracellular vesicles (EV) 82 . In contradiction to this idea, a very recent study in yeast suggests Vps60 to act downstream of Snf7, Vps2 and Vps24, as recruitment of Vps60 to endosomal membrane was distributed in Snf7, Vps2 and Vps24 knockout mutants 83 .…”

Mesenchymal Stem Cell-Derived Exosomes and MicroRNAs in Cartilage Regeneration: Biogenesis, Efficacy, miRNA Enrichment and Delivery

“…After further interacting with ESCRTs I/II and forming a total complex with ESCRT III, plasma membrane infolding begins, resulting in the formation of a cup-shaped early endosome that contains cell-surface proteins and soluble bioactive substances that are accumulated from the extracellular environment. As this early endosome buds inward, it matures into a late endosome that subsequently undergoes a secondary endosomal membrane invagination to form a multivesicular body containing intraluminal vesicles [80,[83][84][85][86]. These intraluminal vesicles have similar membrane positioning to the cell surface, where extracellular domains of transmembrane protein face the extracellular environment while enclosing the cytosolic entities [87].…”