ActA

Definition

ActA is a bacterial surface protein that facilitates the movement of Listeria monocytogenes within host cells by inducing actin polymerization. This process allows the bacteria to spread from cell to cell, evading the immune system.

5 Must Know Facts For Your Next Test

1. Listeria monocytogenes uses ActA to hijack the host cell's actin machinery for motility.
2. ActA-mediated actin polymerization forms comet tails that propel the bacteria through the cytoplasm.
3. This mechanism aids Listeria in spreading directly from one host cell to another, bypassing extracellular immune defenses.
4. Mutations in the ActA gene can reduce or abolish Listeria's ability to move within cells and spread.
5. ActA is critical for Listeria pathogenicity and plays a key role in its virulence.

Review Questions

Related terms

Listeriolysin O: a pore-forming toxin that helps Listeria escape from phagosomes into the cytoplasm

Internalin: a family of proteins that mediate the entry of Listeria into host cells

Phagosome:

a vesicle formed around a particle engulfed by phagocytosis, typically where some pathogens are initially contained before escaping