Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Actin Filaments and the Growth, Movement, and Spread of the Intracellular Bacterial Parasite, Listeria monocytogenes

Lewis G. Tilney and Daniel A. Portnoy
The Journal of Cell Biology
Vol. 109, No. 4, Part 1 (Oct., 1989), pp. 1597-1608
Stable URL: http://www.jstor.org/stable/1613660
Page Count: 12
  • More info
  • Cite this Item
Actin Filaments and the Growth, Movement, and Spread of the Intracellular Bacterial Parasite, Listeria monocytogenes
Preview not available

Abstract

Listeria monocytogenes was used as a model intracellular parasite to study stages in the entry, growth, movement, and spread of bacteria in a macrophage cell line. The first step in infection is phagocytosis of the Listeria, followed by the dissolution of the membrane surrounding the phagosome presumably mediated by hemolysin secreted by Listeria as nonhemolytic mutants remain in intact vacuoles. Within 2 h after infection, each now cytoplasmic Listeria becomes encapsulated by actin filaments, identified as such by decoration of the actin filaments with subfragment 1 of myosin. These filaments are very short. The Listeria grow and divide and the actin filaments rearrange to form a long tail (often 5 μm in length) extending from only one end of the bacterium, a "comet's tail," in which the actin filaments appear randomly oriented. The Listeria "comet" moves to the cell surface with its tail oriented towards the cell center and becomes encorporated into a cell extension with the Listeria at the tip of the process and its tail trailing into the cytoplasm behind it. This extension contacts a neighboring macrophage that phagocytoses the extension of the first macrophage. Thus, within the cytoplasm of the second macrophage is a Listeria with its actin tail surrounded by a membrane that in turn is surrounded by the phagosome membrane of the new host. Both these membranes are then solubilized by the Listeria and the cycle is repeated. Thus, once inside a host cell, the infecting Listeria and their progeny can spread from cell to cell by remaining intracellular and thus bypass the humoral immune system of the organism. To establish if actin filaments are essential for the spread of Listeria from cell to cell, we treated infected macrophages with cytochalasin D. The Listeria not only failed to spread, but most were found deep within the cytoplasm, rather than near the periphery of the cell. Thin sections revealed that the net of actin filaments is not formed nor is a "comet" tail produced.

Page Thumbnails

  • Thumbnail: Page 
1597
    1597
  • Thumbnail: Page 
1598
    1598
  • Thumbnail: Page 
1599
    1599
  • Thumbnail: Page 
1600
    1600
  • Thumbnail: Page 
1601
    1601
  • Thumbnail: Page 
1602
    1602
  • Thumbnail: Page 
[1603]
    [1603]
  • Thumbnail: Page 
1604
    1604
  • Thumbnail: Page 
1605
    1605
  • Thumbnail: Page 
1606
    1606
  • Thumbnail: Page 
1607
    1607
  • Thumbnail: Page 
1608
    1608