eLife digest | Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation

Open accessCopyright infoDownload PDF

Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation

eLife digest

Affiliation details

University of Glasgow, United Kingdom; Cancer Research United Kingdom Beatson Institute, United Kingdom; University of Vermont, United States

Toxoplasma gondii is a parasite that commonly infects most warm-blooded animals and is thought to affect over two billion people worldwide. In most cases, the infection does not cause any symptoms, although it can lead to serious complications in pregnant women or people with a weakened immune system.

T. gondii has a complex life cycle that involves different stages. During infection, the parasite invades the host cells and replicates inside a specialized cell structure called a ‘parasitophorous vacuole’ until the host cell bursts. The parasite then spreads and infects more host cells. The replication is synchronised, meaning all parasites in a host cell replicate at the same time. It was unclear how the parasites coordinated this process, but some researchers suggested that the parasites remained connected to each other to communicate by exchanging material and information. A good candidate to form such connections is the protein actin, which in many organisms forms filaments that guide the transport of cargo molecules in the cell. However, previous research indicated that actin in T. gondii is incapable of forming these stable filaments.

Periz et al. developed a new tool of fluorescence markers that specifically bind to actin in T. gondii and found extensive actin networks that connected parasites with each other and also to the membrane of the parasitophorous vacuole. Actin was needed to transport molecules between the parasites within a vacuole and was also found to enter the cells of the parasite. When the protein was depleted in the parasite, the network collapsed; the parasites started to replicate at different times and could no longer leave the host cell.

A next step will be to further investigate the role of actin in T. gondii and other parasites using the tools developed by Periz et al. A better understanding of replication of T. gondii could provide clues to new treatments for parasitic diseases that cause substantial economic losses worldwide.

DOI: http://dx.doi.org/10.7554/eLife.24119.002