title: The N'-terminal domain of glyceraldehyde-3-phosphate dehydrogenase of the apicomplexan Plasmodium falciparum mediates GTPase Rab2-dependent recruitment to membranes.
abstract: Spatial and temporal distribution of the glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase (pfGAPDH) and aldolase (pfAldolase) of Plasmodium falciparum were investigated using specific mAbs and indirect immunofluorescence analysis (IFA). Both glycolytic enzymes were co-localized during ring and trophozoite stages of both liver and asexual blood stage parasites. During schizogony, pfGAPDH became associated with the periphery of the parasites and eventually accumulated in the apical region of merozoites, while pfAldolase showed no segregation. Subcellular fractionation experiments demonstrated that pfGAPDH was found in both the membrane-containing pellet and the supernatant fraction of parasite lysates. In contrast, pfAldolase was only found in the supernatant fraction. A quantitative binding assay showed that pfGAPDH could be recruited to HeLa cell microsomal membranes in response to mammalian GTPase Rab2, indicating that Rab2-dependent recruitment of cytosolic components to membranes is conserved in evolution. Two overlapping fragments of pfGAPDH (residues 1-192 and 133-337) were evaluated in the microsomal binding assay. We found that the N'-terminal fragment competitively inhibited Rab2-stimulated pfGAPDH recruitment. Thus, the domain mediating the evolutionarily conserved Rab2-dependent membrane recruitment is located in the N'-terminus of GAPDH. Together, these results suggest that pfGAPDH exerts non-glycolytic function(s) in P. falciparum, possibly including a role in vesicular transport and biogenesis of apical organelles.
authors.affiliation: Molecular Immunology, Swiss Tropical Institute, Socinstr. 57, CH-4002 Basel, Switzerland.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Daubenberger
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Tisdale
authors.forename: Marija
authors.initials: M
authors.lastname: Curcic
authors.forename: Diana
authors.initials: D
authors.lastname: Diaz
authors.forename: Olivier
authors.initials: O
authors.lastname: Silvie
authors.forename: Dominique
authors.initials: D
authors.lastname: Mazier
authors.forename: Wijnand
authors.initials: W
authors.lastname: Eling
authors.forename: Bernd
authors.initials: B
authors.lastname: Bohrmann
authors.forename: Hugues
authors.initials: H
authors.lastname: Matile
authors.forename: Gerd
authors.initials: G
authors.lastname: Pluschke
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000276:immunology; D004912:Erythrocytes / Q000469:parasitology; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D006367:HeLa Cells; D022781:Hepatocytes / Q000469:parasitology; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D018613:Microscopy, Confocal; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D011485:Protein Binding; D020693:rab2 GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D020693:rab2 GTP-Binding Protein; D005634:Fructose-Bisphosphate Aldolase