VPS60

PF3D7_1441800 (VPS60) is a component of the Plasmodium falciparum ESCRT-III machinery that drives extracellular vesicle (EV) biogenesis and links vesicular trafficking to parasite proteostasis (PMID:33798247, PMID:42253101). Genetic disruption of VPS60 reduces EV production and perturbs the distribution of other ESCRT-III components, and purified recombinant PfVps60 acts together with PfVps32 and PfBro1 to reconstitute multivesicular body formation and membrane shedding in giant unilamellar vesicles; PfVps60 is itself detected in EVs purified from parasitized red blood cell cultures (PMID:33798247). Recruitment of this ESCRT-III sub-complex proceeds through a non-canonical route in which PfBro1 acts upstream of PfVps32 and PfVps60 (PMID:33798247). Functionally, VPS60 is required for EV-mediated export of the chaperones PfHsp70-x and PfHsp110 under heat shock, and its loss alters protein aggregate dynamics, dampens induction of cytosolic PfHsp70-1, and causes early loss of parasite viability after heat shock, a defect partially rescued by supplying EVs from heat-stressed wild-type parasites (PMID:42253101).

1. 2021 High

   Whether PF3D7_1441800 functions in the parasite's ESCRT machinery and contributes to vesicle formation was unknown; establishing this defined its role in EV biogenesis.

   Evidence Genetic knockout reducing EV number, in vitro reconstitution of MVB formation and membrane shedding in giant unilamellar vesicles with recombinant PfVps60/PfVps32/PfBro1, super-resolution microscopy and dot blot detection in EVs

   PMID:33798247

   Open questions at the time

   • Structural basis of PfVps60 membrane remodeling not resolved
   • Stoichiometry and assembly geometry of the reconstituted complex not defined
   • Cargo selectivity of VPS60-dependent EVs not addressed in this study
2. 2021 Medium

   How the ESCRT-III sub-complex including VPS60 is recruited was unclear; ordering PfBro1 upstream of PfVps32 and PfVps60 revealed a non-canonical recruitment pathway.

   Evidence Functional reconstitution with purified recombinant proteins combined with genetic knockout analysis

   PMID:33798247

   Open questions at the time

   • Recruitment order inferred from reconstitution rather than direct in-cell temporal measurement
   • Molecular interface between PfBro1 and PfVps60 not mapped
   • Whether additional adaptors participate in recruitment is unknown
3. 2026 Medium

   Whether VPS60-dependent EVs serve a physiological function was open; linking VPS60 loss to failed chaperone export and heat-shock survival established a role in EV-dependent proteostasis.

   Evidence PfVps60KO line in P. falciparum 3D7 with proteomic profiling, aggregate-distribution microscopy, viability assays, and dose-dependent EV supplementation rescue

   PMID:42253101

   Open questions at the time

   • Molecular mechanism by which chaperones are loaded into VPS60-dependent EVs is unknown
   • How exported EV chaperones act on recipient cells or the parasite surface is undefined
   • Only partial rescue achieved, leaving other VPS60-dependent functions unaccounted for

• The structural mechanism of PfVps60-driven membrane remodeling and the basis of chaperone cargo selection into EVs remain unresolved.
• No structural model of PfVps60 assembly on membranes
• Cargo-sorting mechanism directing PfHsp70-x/PfHsp110 into EVs unknown
• Regulation of VPS60 activity under febrile stress not defined