Expression in mammalian cell cultures reveals interdependent, but distinct, functions for Star and Rhomboid proteins in the processing of the Drosophila transforming-growth-factor-alpha homologue Spitz.
Expression in mammalian cell cultures reveals interdependent, but distinct, functions for Star and Rhomboid proteins in the processing of the Drosophila transforming-growth-factor-alpha homologue Spitz.
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DOI：
10.1042/0264-6021:3630347
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发表时间：
2002-04
期刊：
影响因子：
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通讯作者：
J. Pascall;J. Luck;K. Brown
中科院分区：
文献类型：
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作者：
J. Pascall;J. Luck;K. Brown
我们在这里报道了两种不同的相互依赖的蛋白质，Star和Rhomboid，这两种蛋白质是果蝇表皮生长因子(EGF)受体信号通路的关键决定因素。当我们在哺乳动物细胞中表达果蝇EGF受体配体Spitz时，通过细胞表面蛋白生物素化或免疫细胞化学染色，该蛋白无法转运到质膜。然而，当我们与Spitz共表达Star时，可以证明Spitz向细胞表面运输。只有当我们共表达Spitz、Star和Rhomboid时，才能显示可溶性Spitz蛋白向介质中的释放。综上所述，我们的结果表明，Star是Spitz在细胞内运输所必需的，而菱形是从细胞中释放可溶性Spitz蛋白所必需的。
We report here distinct interdependent functions for two proteins, Star and Rhomboid, that are key determinants of the epidermal-growth-factor (EGF)-receptor signalling pathway in Drosophila. When we expressed the Drosophila EGF-receptor ligand Spitz in mammalian cells, the protein failed to traffic to the plasma membrane, as assessed by either cell-surface protein biotinylation or immunocytochemical staining. However, when we co-expressed Star with Spitz, trafficking of Spitz to the cell surface could be demonstrated. Only when we co-expressed Spitz, Star and Rhomboid could the release of soluble Spitz protein into the medium be shown. Taken together, our results indicate that Star is required for the intracellular trafficking of Spitz, and that Rhomboid is essential for the release of soluble Spitz protein from cells.