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Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes
14:05

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Published on: September 20, 2013

Actin polymerization is induced by Arp2/3 protein complex at the surface of Listeria monocytogenes

M D Welch1, A Iwamatsu, T J Mitchison

  • 1Department of Cellular and Molecular Pharmacology, University of California at San Francisco, 94143, USA. welch@cgl.ucsf.edu

Nature
|January 16, 1997
PubMed

Insights

Listeria monocytogenes propels itself using actin polymerization, driven by a host cell protein complex. This complex, containing actin-related proteins (ARPs), nucleates actin assembly, enabling bacterial motility within host cells.

Area of Science:

  • Cell Biology
  • Microbiology
  • Biochemistry

Background:

  • Pathogenic bacteria like Listeria monocytogenes exhibit directed movement within host cell cytoplasm.
  • Bacterial motility is propelled by actin polymerization at the bacterial surface, forming actin tails.
  • Understanding this actin polymerization mechanism is crucial for controlling cellular actin dynamics.

Purpose of the Study:

  • To elucidate the mechanism of actin polymerization utilized by Listeria monocytogenes.
  • To identify and characterize the host cell factors involved in ActA-dependent actin assembly.
  • To investigate the role of purified host cell protein complexes in bacterial motility.

Main Methods:

  • Purification of an eight-polypeptide host cell protein complex.
  • Assaying the ability of the purified complex to initiate ActA-dependent actin polymerization.
  • Localizing Arp3 subunit in infected tissue culture cells.

Main Results:

  • A purified eight-polypeptide complex was identified as the host cell actin polymerization factor.
  • This complex is sufficient to initiate ActA-dependent actin polymerization and mediate actin tail formation.
  • The complex contains Arp2 and Arp3 actin-related proteins (ARPs), with Arp3 localizing to bacterial surfaces and actin tails.
  • The Arp2/3 complex acts as a template, nucleating actin polymerization.

Conclusions:

  • The purified Arp2/3 complex is essential for Listeria monocytogenes actin-based motility.
  • The Arp2/3 complex functions as an actin nucleation promoting factor in vivo.
  • This study provides insights into the regulation of actin polymerization by bacterial pathogens.

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