The Dissection of SNAREs Reveals Key Factors for Vesicular Trafficking to the Endosome-like Compartment and Apicoplast via the Secretory System in Toxoplasma gondii.
The Dissection of SNAREs Reveals Key Factors for Vesicular Trafficking to the Endosome-like Compartment and Apicoplast via the Secretory System in Toxoplasma gondii.
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作者：
Cao S;Yang J;Fu J;Chen H;Jia H
囊泡运输是真核生物中物质运输的一个基本细胞过程，但细胞内区室的多样性使研究人员无法清楚地了解顶复门中囊泡运输因子（包括SNARE、Tether和Rab GTP酶）的具体功能。在这项研究中，我们分析了SNARE的定位，并探讨其在囊泡运输的弓形虫。我们的结果揭示了SNARE在内质网（ER）中的特异性定位（T。弓形虫Stx 18 [TgStx 18]和TgStx 19）、高尔基体（TgGS 27）和内体样区室（TgStx 10和TgStx 12）。ER和高尔基体驻留的SNARE的条件性消融引起分泌系统的严重缺陷。最重要的是，我们发现了一个针对顶质体的R-SNARE（TgVAMP 4 -2）;据我们所知，这项工作提供了第一个信息，显示了一个SNARE蛋白在内共生细胞器上，并在真核生物的囊泡运输中发挥作用。TgVAMP 4 -2的条件性敲除阻断了TgCPN 60、TgACP、TgATrx 2和TgATrx 1进入顶质体，并干扰了TgAPT 1和TgFtsH 1靶向顶质体的最外膜。总之，我们的研究结果揭示了SNARE在分泌系统中的功能，以及核编码蛋白质向Apicomplexa模式生物内共生细胞器的运输。
Vesicular trafficking is a fundamental cellular process involved in material transport in eukaryotes, but the diversity of the intracellular compartments has prevented researchers from obtaining a clear understanding of the specific functions of vesicular trafficking factors, including SNAREs, tethers, and Rab GTPases, in Apicomplexa. In this study, we analyzed the localization of SNAREs and investigated their roles in vesicular trafficking in Toxoplasma gondii. Our results revealed the specific localizations of SNAREs in the endoplasmic reticulum (ER) (T. gondii Stx18 [TgStx18] and TgStx19), Golgi stacks (TgGS27), and endosome-like compartment (TgStx10 and TgStx12). The conditional ablation of ER- and Golgi-residing SNAREs caused severe defects in the secretory system. Most importantly, we found an R-SNARE (TgVAMP4-2) that is targeted to the apicoplast; to our knowledge, this work provides the first information showing a SNARE protein on endosymbiotic organelles and functioning in vesicular trafficking in eukaryotes. Conditional knockout of TgVAMP4-2 blocked the entrance of TgCPN60, TgACP, TgATrx2, and TgATrx1 into the apicoplast and interfered with the targeting of TgAPT1 and TgFtsH1 to the outermost membrane of the apicoplast. Together, our findings revealed the functions of SNAREs in the secretory system and the transport of nucleus-encoded proteins to an endosymbiotic organelle in a model organism of Apicomplexa.