title: Aldolase is essential for energy production and bridging adhesin-actin cytoskeletal interactions during parasite invasion of host cells.
abstract: Apicomplexan parasites rely on actin-based motility to drive host cell invasion. Prior in vitro studies implicated aldolase, a tetrameric glycolytic enzyme, in coupling actin filaments to the parasite's surface adhesin microneme protein 2 (MIC2). Here, we test the essentiality of this interaction in host cell invasion. Based on in vitro studies and homology modeling, we generated a series of mutations in Toxoplasma gondii aldolase (TgALD1) that delineated MIC2 tail domain (MIC2t) binding function from its enzyme activity. We tested these mutants by complementing a conditional knockout of TgALD1. Mutations that affected glycolysis also reduced motility. Mutants only affecting binding to MIC2t had no motility phenotype, but were decreased in their efficiency of host cell invasion. Our studies demonstrate that aldolase is not only required for energy production but is also essential for efficient host cell invasion, based on its ability to bridge adhesin-cytoskeleton interactions in the parasite.
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63130-1093, USA.
authors.forename: G Lucas
authors.initials: GL
authors.lastname: Starnes
authors.forename: Mathieu
authors.initials: M
authors.lastname: Coincon
authors.forename: Jurgen
authors.initials: J
authors.lastname: Sygusch
authors.forename: L David
authors.initials: LD
authors.lastname: Sibley
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D004734:Energy Metabolism; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D006790:Host-Parasite Interactions; D008565:Membrane Proteins / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D014122:Toxoplasma / Q000502:physiology*; D014774:Virulence
chemical_list: D000199:Actins; C408878:MIC2 protein, Toxoplasma gondii; D008565:Membrane Proteins; D015800:Protozoan Proteins; D005634:Fructose-Bisphosphate Aldolase