Thind Amara C, Mead Andrew J, Quan Justin J, Sha Jihui, Wohlschlegel James A, Bradley Peter J
Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095.
Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095.
Mol Biol Cell. 2025 Aug 1;36(8):ar97. doi: 10.1091/mbc.E24-07-0322. Epub 2025 Jun 4.
and its relative are apicomplexan pathogens that secrete an array of dense granule proteins into the parasitophorous vacuole and host cell, where they play roles in acquiring nutrients and modulating host cell functions. Here, we characterize the novel GRA protein GRA84 in and , which is secreted into the PV and exported into the host cell nucleus. Disruption of does not affect in vitro parasite replication or establishment or maintenance of the chronic infection in vivo. We show that this effector uses the MYR translocon to traverse the vacuolar membrane and is dependent on the aspartyl protease ASP5 for its export to the host nucleus. We demonstrate that GRA84 undergoes processing that removes over 90 amino acids from its N-terminus, an event that is independent of ASP5. We also use mutagenesis to disrupt processing and show that maturation is critical for transit across the vacuolar membrane. Taken together, this work identifies GRA84 in both and and reveals an unusual processing event that is necessary for maturation of the protein and export of the effector into the host cell.
其相关物是顶复门病原体，它们向寄生泡和宿主细胞分泌一系列致密颗粒蛋白，这些蛋白在获取营养和调节宿主细胞功能中发挥作用。在这里，我们鉴定了疟原虫和巴贝斯虫中的新型致密颗粒蛋白GRA84，它被分泌到寄生泡中并输出到宿主细胞核中。破坏GRA84并不影响体外寄生虫复制或体内慢性感染的建立或维持。我们表明，这种效应蛋白利用MYR转运体穿越液泡膜，并且其输出到宿主细胞核依赖于天冬氨酸蛋白酶ASP5。我们证明GRA84会经历加工过程，从其N端去除超过90个氨基酸，这一事件独立于ASP5。我们还使用诱变来破坏加工过程，并表明成熟对于穿过液泡膜至关重要。综上所述，这项工作鉴定了疟原虫和巴贝斯虫中的GRA84，并揭示了一种不寻常的加工事件，这是该蛋白成熟以及效应蛋白输出到宿主细胞所必需的。
