Shigella interactions with the actin cytoskeleton in the absence of Ena/VASP family proteins.
Shigella move through the cytosol of infected cells by assembly of a propulsive actin tail at one end of the bacterium. Vasodilator-stimulated phosphoprotein (VASP), a member of the Ena/VASP family of proteins, is important in cellular actin dynamics and is present on intracellular Shigella. VASP binds both profilin, an actin monomer-binding protein, and vinculin, a component of intercellular contacts that also binds the Shigella actin assembly protein IcsA. It has been postulated that VASP might serve as a linker between vinculin and profilin on intracellular Shigella, thereby delivering profilin to the Shigella actin assembly machinery. We show that Shigella actin-based motility is unaltered in cells that are deficient for the Ena/VASP family of proteins. In these cells, Shigella form normal-appearing actin tails and move at rates that are comparable to the rates of bacterial movement in Ena/VASP-deficient cells complemented with the Ena/VASP family member Mena. Finally, whereas vinculin can bind the Arp2/3 complex, we show that Arp2/3 recruitment to Shigella is not correlated with vinculin recruitment, indicating that the role of vinculin in Shigella motility is not recruitment of Arp2/3. Thus, although VASP is recruited to the surface of intracellular Shigella, it is not essential for Shigella actin-based motility.
Ally
Shabeen
S
Infectious Disease Division, Massachusetts General Hospital, Cambridge, MA 02139, USA.
Sauer
Noel J
NJ
Loureiro
Joseph J
JJ
Snapper
Scott B
SB
Gertler
Frank B
FB
Goldberg
Marcia B
MB
D000199:Actins / Q000502:physiology*; D000818:Animals; D001426:Bacterial Proteins / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000502:physiology; D002478:Cells, Cultured; D003285:Contractile Proteins / Q000378:metabolism; D003593:Cytoplasm / Q000382:microbiology; D003598:Cytoskeletal Proteins / Q000502:physiology*; D005347:Fibroblasts; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism; D009068:Movement; D010750:Phosphoproteins / Q000032:analysis / Q000502:physiology; D051304:Profilins; D012763:Shigella flexneri / Q000166:cytology / Q000502:physiology*; D016596:Vinculin / Q000378:metabolism; D000098662:Vasodilator-Stimulated Phosphoprotein
D000199:Actins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D003285:Contractile Proteins; D003598:Cytoskeletal Proteins; C102176:Enah protein, mouse; D008840:Microfilament Proteins; C495738:PFN1 protein, human; D010750:Phosphoproteins; D051304:Profilins; D000098662:Vasodilator-Stimulated Phosphoprotein; D016596:Vinculin