Rounding precedes rupture and breakdown of vacuolar membranes minutes before malaria parasite egress from erythrocytes

Cell Microbiol. 2018 Oct;20(10):e12868. doi: 10.1111/cmi.12868. Epub 2018 Jul 10.

Abstract

Because Plasmodium falciparum replicates inside of a parasitophorous vacuole (PV) within a human erythrocyte, parasite egress requires the rupture of two limiting membranes. Parasite Ca2+ , kinases, and proteases contribute to efficient egress; their coordination in space and time is not known. Here, the kinetics of parasite egress were linked to specific steps with specific compartment markers, using live-cell microscopy of parasites expressing PV-targeted fluorescent proteins, and specific egress inhibitors. Several minutes before egress, under control of parasite [Ca2+ ]i , the PV began rounding. Then after ~1.5 min, under control of PfPKG and SUB1, there was abrupt rupture of the PV membrane and release of vacuolar contents. Over the next ~6 min, there was progressive vacuolar membrane deterioration simultaneous with erythrocyte membrane distortion, lasting until the final minute of the egress programme when newly formed parasites mobilised and erythrocyte membranes permeabilised and then ruptured-a dramatic finale to the parasite cycle of replication.

Keywords: Plasmodium falciparum; infection; membrane; microbial structure; microbial-cell interaction; parasitophorous vacuole.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Calcium / metabolism
  • Erythrocyte Membrane / parasitology*
  • Erythrocytes / parasitology*
  • Erythrocytes / pathology*
  • Fluorescent Dyes
  • Humans
  • Malaria, Falciparum / parasitology
  • Malaria, Falciparum / pathology
  • Plasmodium falciparum / growth & development*
  • Plasmodium falciparum / metabolism
  • Protein Serine-Threonine Kinases / metabolism
  • Vacuoles / metabolism
  • Vacuoles / parasitology*

Substances

  • Fluorescent Dyes
  • Protein Serine-Threonine Kinases
  • Calcium