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Wiskott-Aldrich syndrome protein (WASP) and N-WASP have emerged as key proteins connecting signalling cascades to actin polymerization. Here we show that the amino-terminal WH1 domain, and not the polyproline-rich region, of N-WASP is responsible for its recruitment to sites of actin polymerization during Cdc42-independent, actin-based motility of vaccinia(More)
Vaccinia virus, a close relative of the causative agent of smallpox, exploits actin polymerization to enhance its cell-to-cell spread. We show that actin-based motility of vaccinia is initiated only at the plasma membrane and remains associated with it. There must therefore be another form of cytoplasmic viral transport, from the cell centre, where the(More)
Caveolins are integral membrane proteins which are a major component of caveolae. In addition, caveolins have been proposed to cycle between intracellular compartments and the cell surface but the exact trafficking route and targeting information in the caveolin molecule have not been defined. We show that antibodies against the caveolin scaffolding domain(More)
Recognition of virus presence via RIG-I (retinoic acid inducible gene I) and/or MDA5 (melanoma differentiation-associated protein 5) initiates a signaling cascade that culminates in transcription of innate response genes such as those encoding the alpha/beta interferon (IFN-alpha/beta) cytokines. It is generally assumed that MDA5 is activated by long(More)
Lamellipodial protrusion is regulated by Ena/VASP proteins. We identified Lamellipodin (Lpd) as an Ena/VASP binding protein. Both proteins colocalize at the tips of lamellipodia and filopodia. Lpd is recruited to EPEC and Vaccinia, pathogens that exploit the actin cytoskeleton for their own motility. Lpd contains a PH domain that binds specifically to(More)
Studies of the actin-based motility of the intracellular pathogens Listeria monocytogenes and Shigella flexneri have provided important insight into the events occurring at the leading edges of motile cells. Like the bacteria Listeria and Shigella, vaccinia virus, a relative of the causative agent of smallpox, uses actin-based motility to spread between(More)
The N-terminal head domain of human dystrophin has been expressed in soluble form and high yield in E. coli, allowing us to test the previously unconfirmed assumption that dystrophin binds actin. DMD246, the first 246 amino acid residues of dystrophin, binds F-actin in a strongly co-operative manner with a Hill constant of 3.5, but does not bind G-actin.(More)
The F-actin binding domains of gelsolin and alpha-actinin compete for the same site on actin filaments with similar binding affinities. Both contain tandem repeats of approximately 125 amino acids, the first of which is shown to contain the actin-binding site. We have replaced the F-actin binding domain in the NH2-terminal half of gelsolin by that of(More)
BACKGROUND Actin assembly on biological membranes is a poorly understood process. We have previously shown that phagosomal membranes could induce actin assembly in the presence of thymosin beta4 (an actin sequestering protein that inhibits nonspecific nucleation), via the barbed ends of actin filaments. METHODS Here, we have developed an in vitro system(More)