title: Reconstitution of actin-based motility of Listeria and Shigella using pure proteins.
abstract: Actin polymerization is essential for cell locomotion and is thought to generate the force responsible for cellular protrusions. The Arp2/3 complex is required to stimulate actin assembly at the leading edge in response to signalling. The bacteria Listeria and Shigella bypass the signalling pathway and harness the Arp2/3 complex to induce actin assembly and to propel themselves in living cells. However, the Arp2/3 complex alone is insufficient to promote movement. Here we have used pure components of the actin cytoskeleton to reconstitute sustained movement in Listeria and Shigella in vitro. Actin-based propulsion is driven by the free energy released by ATP hydrolysis linked to actin polymerization, and does not require myosin. In addition to actin and activated Arp2/3 complex, actin depolymerizing factor (ADF, or cofilin) and capping protein are also required for motility as they maintain a high steady-state level of G-actin, which controls the rate of unidirectional growth of actin filaments at the surface of the bacterium. The movement is more effective when profilin, alpha-actinin and VASP (for Listeria) are also included. These results have implications for our understanding of the mechanism of actin-based motility in cells.
authors.affiliation: Dynamique du Cytosquelette, LEBS, CNRS, Gif-sur-Yvette, France.
authors.forename: T P
authors.initials: TP
authors.lastname: Loisel
authors.forename: R
authors.initials: R
authors.lastname: Boujemaa
authors.forename: D
authors.initials: D
authors.lastname: Pantaloni
authors.forename: M F
authors.initials: MF
authors.lastname: Carlier
mesh_terms: D051339:Actin Depolymerizing Factors; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D001426:Bacterial Proteins; D002417:Cattle; D015815:Cell Adhesion Molecules / Q000502:physiology; D003285:Contractile Proteins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000502:physiology; D004926:Escherichia coli / Q000502:physiology; D006801:Humans; D008089:Listeria monocytogenes / Q000502:physiology*; D008840:Microfilament Proteins / Q000502:physiology; D009068:Movement; D009419:Nerve Tissue Proteins / Q000502:physiology; D010750:Phosphoproteins / Q000502:physiology; D051304:Profilins; D011817:Rabbits; D011994:Recombinant Proteins; D012760:Shigella / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051339:Actin Depolymerizing Factors; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D001426:Bacterial Proteins; D015815:Cell Adhesion Molecules; D003285:Contractile Proteins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D051304:Profilins; D011994:Recombinant Proteins; D014157:Transcription Factors; C495771:WASL protein, human; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D000098662:Vasodilator-Stimulated Phosphoprotein; C058483:virG protein, Shigella flexneri; D000255:Adenosine Triphosphate