Neighbors Working Together: a Toxoplasma Rhoptry Protein That Facilitates Dense Granule Protein Translocation into the Host Cell

The opportunistic pathogen Toxoplasma gondii is highly adept at manipulating host cell functions. While inside a host cell, Toxoplasma divides within a parasitophorous vacuole from which it secretes numerous effector proteins from its dense granules. Many of these so-called GRA proteins are translocated from the parsitophorous vacuole into the host cell where they directly disrupt host signaling pathways. The machinery that drives the translocation of GRA proteins across the parasitophorous vacuole membrane is being elucidated through both genetic and biochemical approaches. A new mSphere research article (M. W. Panas, A. Ferrel, A. Naor, E. Tenborg, et al., mSphere 4:e00276-19, 2019, https://doi.org/10.1128/mSphere.00276-19) describes how the kinase ROP17, which is secreted from the parasite’s rhoptries into the host cell during invasion, regulates the translocation of GRA effectors.