Interaction of α-taxilin Localized on Intracellular Components with the Microtubule Cytoskeleton
Interaction of α-taxilin Localized on Intracellular Components with the Microtubule Cytoskeleton
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DOI：
10.1247/csf.12002
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发表时间：
2012-01-01
影响因子：
1.5
通讯作者：
Shirataki, Hiromichi
中科院分区：
文献类型：
--
作者：
Horii, Yukimi;Nogami, Satoru;Shirataki, Hiromichi
胞内囊泡运输在细胞器特性的建立和维持以及生物合成运输中起着至关重要的作用。我们已经确定α-紫杉素作为结合伴侣的syntaxin家族，这是参与细胞内囊泡交通。近年来，我们发现α-taxilin在肝细胞癌和肾细胞癌等恶性肿瘤组织中过度表达。然而，α-紫杉醇在细胞内囊泡交通和致癌作用的确切作用仍不清楚。然后，我们首先研究了α-紫杉醇在Hela细胞中的细胞内分布。免疫荧光研究表明，α-紫杉素分布在整个细胞质中，并表现出管状泡状图案。生物化学研究表明，α-紫杉素作为外周膜蛋白大量定位于细胞内组分。此外，我们发现α-紫杉素分布在微管依赖性和突触融合蛋白的非依赖性的方式，α-紫杉素直接结合到聚合微管蛋白在体外，和N-乙基马来酰亚胺，而不是布雷菲德菌素A影响α-紫杉素的细胞内分布。这些结果表明，α-紫杉素是本地化的细胞内成分中的突触融合蛋白的独立的方式和α-紫杉素的细胞内成分与微管细胞骨架，并建议α-紫杉素的功能作为一个接头蛋白之间的α-紫杉素的细胞内成分和微管细胞骨架。
Intracellular vesicle traffic plays an essential role in the establishment and maintenance of organelle identity and biosynthetic transport. We have identified alpha-taxilin as a binding partner of the syntaxin family, which is involved in intracellular vesicle traffic. Recently, we have found that alpha-taxilin is over-expressed in malignant tissues including hepatocellular carcinoma and renal cell carcinoma. However, a precise role of alpha-taxilin in intracellular vesicle traffic and carcinogenesis remains unclear. Then, we first investigated here the intracellular distribution of alpha-taxilin in Hela cells. Immunofluorescence studies showed that alpha-taxilin distributes throughout the cytoplasm and exhibits a tubulo-vesicular pattern. Biochemical studies showed that alpha-taxilin is abundantly localized on intracellular components as a peripheral membrane protein. Moreover, we found that alpha-taxilin distributes in microtubule-dependent and syntaxin-independent manners, that alpha-taxilin directly binds to polymerized tubulin in vitro, and that N-ethylmaleimide but not brefeldin A affects the intracellular distribution of alpha-taxilin. These results indicate that alpha-taxilin is localized on intracellular components in a syntaxin-independent manner and that the alpha-taxilin-containing intracellular components are associated with the microtubule cytoskeleton and suggest that alpha-taxilin functions as a linker protein between the alpha-taxilin-containing intracellular components and the microtubule cytoskeleton.