Transport of proteins and lipids from one membrane compartment to another is via intracellular vesicles. We investigated the function of tumor protein D54 (TPD54/TPD52L2) and found that TPD54 was involved in multiple membrane trafficking pathways: anterograde traffic, recycling, and Golgi integrity. To understand how TPD54 controls these diverse functions, we used an inducible method to reroute TPD54 to mitochondria. Surprisingly, this manipulation resulted in the capture of many small vesicles (30 nm diameter) at the mitochondrial surface. Super-resolution imaging confirmed the presence of similarly sized TPD54-positive structures under normal conditions. It appears that TPD54 defines a new class of transport vesicle, which we term intracellular nanovesicles (INVs). INVs meet three criteria for functionality. They contain specific cargo, they have certain R-SNAREs for fusion, and they are endowed with a variety of Rab GTPases (16 out of 43 tested). The molecular heterogeneity of INVs and the diverse functions of TPD54 suggest that INVs have various membrane origins and a number of destinations. We propose that INVs are a generic class of transport vesicle that transfer cargo between these varied locations.

中文翻译：

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肿瘤蛋白 D54 定义了一类新的细胞内转运囊泡


蛋白质和脂质从一个膜室运输到另一个膜室是通过细胞内囊泡。我们研究了肿瘤蛋白 D54 (TPD54/TPD52L2) 的功能，发现 TPD54 参与多种膜运输途径：顺行运输、再循环和高尔基体完整性。为了了解 TPD54 如何控制这些不同的功能，我们使用诱导方法将 TPD54 重新路由至线粒体。令人惊讶的是，这种操作导致在线粒体表面捕获许多小囊泡（直径 30 nm）。超分辨率成像证实在正常条件下存在类似大小的 TPD54 阳性结构。 TPD54 似乎定义了一类新的运输囊泡，我们将其称为细胞内纳米囊泡 (INV)。 INV 满足三个功能标准。它们含有特定的货物，它们有某些用于融合的 R-SNARE，并且它们被赋予了多种 Rab GTPases（43 个测试中的 16 个）。 INV 的分子异质性和 TPD54 的多样化功能表明 INV 具有不同的膜起源和许多目的地。我们认为 INV 是一类通用的运输囊泡，可以在这些不同地点之间转移货物。