The ActA protein is responsible for the actin-based movement of Listeria monocytogenes in the cytosol of eukaryotic cells. Analysis of mutants in which we varied the number of proline-rich repeats (PRR; consensus sequence DFPPPPTDEEL) revealed a linear relationship between the number of PRRs and the rate of movement, with each repeat contributing approximately 2-3 microns/min. Mutants lacking all functional PRRs (generated by deletion or point mutation) moved at rates 30% of wild-type. Indirect immunofluorescence indicated that the PRRs were directly responsible for binding of vasodilator-stimulated phosphoprotein (VASP) and for the localization of profilin at the bacterial surface. The long repeats, which are interdigitated between the PRRs, increased the frequency with which actin-based motility occurred by a mechanism independent of the PRRs, VASP, and profilin. Lastly, a mutant which expressed low levels of ActA exhibited a phenotype indicative of a threshold; there was a very low percentage of moving bacteria, but when movement did occur, it was at wild-type rates. These results indicate that the ActA protein directs at least three separable events: (1) initiation of actin polymerization that is independent of the repeat region; (2) initiation of movement dependent on the long repeats and the amount of ActA; and (3) movement rate dependent on the PRRs.
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1 November 1996
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November 01 1996
The tandem repeat domain in the Listeria monocytogenes ActA protein controls the rate of actin-based motility, the percentage of moving bacteria, and the localization of vasodilator-stimulated phosphoprotein and profilin.
G A Smith,
G A Smith
Department of Microbiology, University of Pennsylvania, School of Medicine, Philadelphia 19104-4318, USA.
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J A Theriot,
J A Theriot
Department of Microbiology, University of Pennsylvania, School of Medicine, Philadelphia 19104-4318, USA.
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D A Portnoy
D A Portnoy
Department of Microbiology, University of Pennsylvania, School of Medicine, Philadelphia 19104-4318, USA.
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G A Smith
Department of Microbiology, University of Pennsylvania, School of Medicine, Philadelphia 19104-4318, USA.
J A Theriot
Department of Microbiology, University of Pennsylvania, School of Medicine, Philadelphia 19104-4318, USA.
D A Portnoy
Department of Microbiology, University of Pennsylvania, School of Medicine, Philadelphia 19104-4318, USA.
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1996) 135 (3): 647–660.
Citation
G A Smith, J A Theriot, D A Portnoy; The tandem repeat domain in the Listeria monocytogenes ActA protein controls the rate of actin-based motility, the percentage of moving bacteria, and the localization of vasodilator-stimulated phosphoprotein and profilin.. J Cell Biol 1 November 1996; 135 (3): 647–660. doi: https://doi.org/10.1083/jcb.135.3.647
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