title: MAHRP2, an exported protein of Plasmodium falciparum, is an essential component of Maurer's cleft tethers.
abstract: Upon invasion into erythrocytes, the malaria parasite Plasmodium falciparum must refurbish the host cell. The objective of this study was to elucidate the location and function of MAHRP2 in these processes. Using immunofluorescence and immunoelectron microscopy we showed that the membrane-associated histidine-rich protein-2 (MAHRP2) is exported during this process to novel cylindrical structures in the erythrocyte cytoplasm. We hypothesize that these structures tether organelles known as Maurer's clefts to the erythrocyte skeleton. Live cell imaging of parasite transfectants expressing MAHRP2-GFP revealed both mobile and fixed populations of the tether-like structures. Differential centrifugation allowed the enrichment of these novel structures. MAHRP2 possesses neither a signal peptide nor a PEXEL motif, and sequences required for export were determined using transfectants expressing truncated MAHRP2 fragments. The first 15 amino acids and the histidine-rich N-terminal region are necessary for correct trafficking of MAHRP2 together with a predicted hydrophobic region. Solubilization studies showed that MAHRP2 is membrane associated but not membrane spanning. Several attempts to delete the mahrp2 gene failed, indicating that the protein is essential for parasite survival.
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland.
authors.forename: Esther
authors.initials: E
authors.lastname: Pachlatko
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rusch
authors.forename: Anouk
authors.initials: A
authors.lastname: Müller
authors.forename: Andrew
authors.initials: A
authors.lastname: Hemphill
authors.forename: Leann
authors.initials: L
authors.lastname: Tilley
authors.forename: Eric
authors.initials: E
authors.lastname: Hanssen
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Beck
mesh_terms: D020816:Amino Acid Motifs; D004912:Erythrocytes / Q000737:chemistry* / Q000469:parasitology; D017353:Gene Deletion; D020043:Genes, Essential; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism*; D021382:Protein Sorting Signals; D011506:Proteins / Q000032:analysis* / Q000235:genetics; D015800:Protozoan Proteins / Q000032:analysis* / Q000235:genetics; D000099053:Histidine-Rich Glycoprotein
chemical_list: D008565:Membrane Proteins; D021382:Protein Sorting Signals; D011506:Proteins; D015800:Protozoan Proteins; D000099053:Histidine-Rich Glycoprotein; D049452:Green Fluorescent Proteins