title: Organization and function of an actin cytoskeleton in Plasmodium falciparum gametocytes.
abstract: In preparation for transmission to its mosquito vector, Plasmodium falciparum, the most virulent of the human malaria parasites, adopts an unusual elongated shape. Here we describe a previously unrecognized actin-based cytoskeleton that is assembled in maturing P. falciparum gametocytes. Differential extraction reveals the presence of a highly stabilized population of F-actin at all stages of development. Super-resolution microscopy reveals an F-actin cytoskeleton that is concentrated at the ends of the elongating gametocyte but extends inward along the microtubule cytoskeleton. Formin-1 is also concentrated at the gametocyte ends suggesting a role in actin stabilization. Immunoelectron microscopy confirms that the actin cytoskeleton is located under the inner membrane complex rather than in the sub-alveolar space. In stage V gametocytes, the actin and microtubule cytoskeletons are reorganized in a coordinated fashion. The actin-depolymerizing agent, cytochalasin D, depletes actin from the end of the gametocytes, whereas the actin-stabilizing compound, jasplakinolide, induces formation of large bundles and prevents late-stage disassembly of the actin cytoskeleton. Long-term treatment with these compounds is associated with disruption of the normal mitochondrial organization and decreased gametocyte viability.
authors.affiliation: Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, Melbourne, Vic., 3010, Australia; Australian Research Council Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Melbourne, Vic., 3010, Australia; School of Botany, The University of Melbourne, Melbourne, Vic., 3010, Australia.
authors.forename: Marion
authors.initials: M
authors.lastname: Hliscs
authors.forename: Coralie
authors.initials: C
authors.lastname: Millet
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Dixon
authors.forename: Inga
authors.initials: I
authors.lastname: Siden-Kiamos
authors.forename: Paul
authors.initials: P
authors.lastname: McMillan
authors.forename: Leann
authors.initials: L
authors.lastname: Tilley
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D008853:Microscopy; D010963:Plasmodium falciparum / Q000737:chemistry*; D055503:Protein Multimerization