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Actin-based motility of intracellular microbial pathogens
1Infectious Disease Division, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. mgoldberg1@partners.org
Abstract:
A diverse group of intracellular microorganisms, including Listeria monocytogenes, Shigella spp., Rickettsia spp., and vaccinia virus, utilize actin-based motility to move within and spread between mammalian host cells. These organisms have in common a pathogenic life cycle that involves a stage within the cytoplasm of mammalian host cells. Within the cytoplasm of host cells, these organisms activate components of the cellular actin assembly machinery to induce the formation of actin tails on the microbial surface. The assembly of these actin tails provides force that propels the organisms through the cell cytoplasm to the cell periphery or into adjacent cells. Each of these organisms utilizes preexisting mammalian pathways of actin rearrangement to induce its own actin-based motility. Particularly remarkable is that while all of these microbes use the same or overlapping pathways, each intercepts the pathway at a different step. In addition, the microbial molecules involved are each distinctly different from the others. Taken together, these observations suggest that each of these microbes separately and convergently evolved a mechanism to utilize the cellular actin assembly machinery. The current understanding of the molecular mechanisms of microbial actin-based motility is the subject of this review.
Insights
Intracellular pathogens like Listeria and Shigella hijack host cell actin to move. These microbes evolved distinct mechanisms to exploit common cellular pathways for actin-based motility.
Area of Science:
- Microbiology
- Cell Biology
- Molecular Biology
Background:
- Intracellular microorganisms exhibit actin-based motility for host cell invasion and spread.
- Pathogenic bacteria (Listeria, Shigella) and viruses (vaccinia) utilize host cell cytoplasm for replication and movement.
Purpose of the Study:
- To review the molecular mechanisms of microbial actin-based motility.
- To explore how diverse microbes convergently evolved to exploit host cell actin dynamics.
Main Methods:
- Review of existing literature on microbial actin-based motility.
- Analysis of molecular pathways used by Listeria monocytogenes, Shigella spp., Rickettsia spp., and vaccinia virus.
- Comparison of microbial strategies for hijacking host cell actin assembly.
Main Results:
- Diverse microbes utilize host cell actin assembly machinery for propulsion within host cells.
- Each microbe employs unique molecular strategies to engage overlapping actin pathways.
- Convergent evolution is suggested by distinct microbial molecules utilizing common host pathways.
Conclusions:
- Microbial actin-based motility represents a remarkable example of convergent evolution.
- Understanding these mechanisms provides insights into host-pathogen interactions.
- Further research can elucidate the precise molecular interactions and evolutionary strategies.