Hardly Vacuous: The Parasitophorous Vacuolar Membrane of Malaria Parasites

Abstract

When a malaria parasite invades a host erythrocyte it pushes itself in and invaginates a portion of the host membrane, thereby sealing itself inside and establishing itself in the resulting vacuole. The parasitophorous vacuolar membrane (PVM) that surrounds the parasite is modified by the parasite, using its secretory organelles. To survive within this enveloping membrane, the organism must take in nutrients, secrete wastes, export proteins into the host cell, and eventually egress. Here, we review current understanding of the unique solutions Plasmodium has evolved to these challenges and discuss the remaining questions.

Defining the Essential Exportome of the Malaria Parasite

“…To survive inside the nutrient-and organelle-deprived mature RBC, that is also subject to routine splenic surveillance, the parasite exports its own proteins to remodel its host cell (Figure 1A) [1]. Early studies in host cell remodelling were mostly interested in deciphering how key parasite adhesins, which determine the severity of malaria in Plasmodium-infected individuals, are trafficked to the surface of the RBC, with the aim of identifying novel strategies that could be used to reduce the clinical burden of the disease (Figure 1A) [2].While establishing its replicative niche, the Plasmodium parasite encapsulates itself within a parasitophorous vacuole membrane (PVM) formed during invasion and derived from an invagination of the host-cell membrane and rhoptry components (Figure 1A) [3,4]. During PVM biogenesis, the parasite also secretes components of a protein-conducting channel known as the Plasmodium translocon of exported proteins (PTEX) to the PVM to assist in the translocation of parasite effector proteins across this membrane (Figure 1A,B) [5,6].…”

“…While establishing its replicative niche, the Plasmodium parasite encapsulates itself within a parasitophorous vacuole membrane (PVM) formed during invasion and derived from an invagination of the host-cell membrane and rhoptry components (Figure 1A) [3,4]. During PVM biogenesis, the parasite also secretes components of a protein-conducting channel known as the Plasmodium translocon of exported proteins (PTEX) to the PVM to assist in the translocation of parasite effector proteins across this membrane (Figure 1A,B) [5,6].…”

Plug for the parasitophorous duct: a solution of two conundra

“…1). The tight junction transmembrane domains would prevent any lateral diffusion of integral membrane proteins across this barrier, consistent of the presence of distinct sets of PVM and RBCM proteins [8,9]. This model allows normal lateral movement of lipids as expected of a continuous bilayer.…”

Duration of Storage Reduced Erythrocytes Profiles and Plasmodium Viability in Donor Blood

“… 31 , 32 A channel on the parasitophorous vacuole membrane (PVM) has been described 33 , 34 and projections from the PVM, called the tubulo-vesicular membrane network (TVM), have been implicated in the acquisition of nutrients. 34 , 35 These mechanisms proposed a direct connection of the Plasmodium spp. to the plasma during prolonged storage.…”