Divergent kinase regulates membrane ultrastructure of the Toxoplasma parasitophorous vacuole
Divergent kinase regulates membrane ultrastructure of the Toxoplasma parasitophorous vacuole
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DOI：
10.1073/pnas.1816161116
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发表时间：
2019-03-26
影响因子：
11.1
通讯作者：
Reese, Michael L.
中科院分区：
文献类型：
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作者：
Beraki, Tsebaot;Hu, Xiaoyu;Reese, Michael L.
顶复门寄生虫在一个保护性的细胞器内复制，称为寄生泡（PV）。弓形虫PV充满了管状膜的网络，这被认为是促进效应物和营养物质的运输。尽管对寄生虫的毒力至关重要，但对网络功能的机械理解很少。在这里，我们确定了寄生虫分泌的激酶WNG1（无甘氨酸环）作为一个重要的调节器的肾小管膜生物合成。WNG1家族成员采用非典型蛋白激酶折叠，缺乏典型激酶中催化所需的富含甘氨酸的ATP结合环。出乎意料的是，我们发现WNG 1是一种活性蛋白激酶，定位于PV腔和磷酸化PV驻留蛋白，其中几个是形成功能性液泡内网络所必需的。此外，我们表明，这些蛋白质的WNG1依赖性磷酸化是必要的，他们的膜协会，因此他们的能力微管膜。因此，WNG1基因敲除的寄生虫具有异常的PV膜超微结构。总的来说，我们的研究结果描述了一个独特的家庭弓形虫激酶和牵连的磷酸化分泌蛋白作为一种机制，调节PV的发展在寄生虫感染。
Apicomplexan parasites replicate within a protective organelle, called the parasitophorous vacuole (PV). The Toxoplasma gondii PV is filled with a network of tubulated membranes, which are thought to facilitate trafficking of effectors and nutrients. Despite being critical to parasite virulence, there is scant mechanistic understanding of the network's functions. Here, we identify the parasite-secreted kinase WNG1 (With-No-Gly-loop) as a critical regulator of tubular membrane biogenesis. WNG1 family members adopt an atypical protein kinase fold lacking the glycine rich ATP-binding loop that is required for catalysis in canonical kinases. Unexpectedly, we find that WNG1 is an active protein kinase that localizes to the PV lumen and phosphorylates PV-resident proteins, several ofwhich are essential for the formation of a functional intravacuolar network. Moreover, we show that WNG1-dependent phosphorylation of these proteins is required for their membrane association, and thus their ability to tubulate membranes. Consequently, WNG1 knockout parasites have an aberrant PV membrane ultrastructure. Collectively, our results describe a unique family of Toxoplasma kinases and implicate phosphorylation of secreted proteins as a mechanism of regulating PV development during parasite infection.