title: PTEX component HSP101 mediates export of diverse malaria effectors into host erythrocytes.
abstract: To mediate its survival and virulence, the malaria parasite Plasmodium falciparum exports hundreds of proteins into the host erythrocyte. To enter the host cell, exported proteins must cross the parasitophorous vacuolar membrane (PVM) within which the parasite resides, but the mechanism remains unclear. A putative Plasmodium translocon of exported proteins (PTEX) has been suggested to be involved for at least one class of exported proteins; however, direct functional evidence for this has been elusive. Here we show that export across the PVM requires heat shock protein 101 (HSP101), a ClpB-like AAA+ ATPase component of PTEX. Using a chaperone auto-inhibition strategy, we achieved rapid, reversible ablation of HSP101 function, resulting in a nearly complete block in export with substrates accumulating in the vacuole in both asexual and sexual parasites. Surprisingly, this block extended to all classes of exported proteins, revealing HSP101-dependent translocation across the PVM as a convergent step in the multi-pathway export process. Under export-blocked conditions, association between HSP101 and other components of the PTEX complex was lost, indicating that the integrity of the complex is required for efficient protein export. Our results demonstrate an essential and universal role for HSP101 in protein export and provide strong evidence for PTEX function in protein translocation into the host cell.
authors.affiliation: 1] Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA [2].
authors.forename: Josh R
authors.initials: JR
authors.lastname: Beck
authors.affiliation: 1] Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA [2] Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, Missouri 63110, USA [3] [4] Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Vasant
authors.initials: V
authors.lastname: Muralidharan
authors.affiliation: 1] Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA [2] Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA [3] Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, Missouri 63110, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Oksman
authors.affiliation: 1] Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA [2] Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA [3] Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, Missouri 63110, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Goldberg
mesh_terms: D004912:Erythrocytes / Q000469:parasitology*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006790:Host-Parasite Interactions / Q000502:physiology*; D008018:Life Cycle Stages / Q000235:genetics; D016778:Malaria, Falciparum / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D021381:Protein Transport; D015800:Protozoan Proteins / Q000378:metabolism*; D014617:Vacuoles / Q000469:parasitology
chemical_list: D006360:Heat-Shock Proteins; D015800:Protozoan Proteins; C502072:cytoadherence-linked asexual protein 3, Plasmodium falciparum