Sphingoid base synthesis requirement for endocytosis in Saccharomyces cerevisiae
Sphingoid base synthesis requirement for endocytosis in Saccharomyces cerevisiae
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DOI：
10.1093/emboj/19.12.2824
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发表时间：
2000-06-15
期刊：
影响因子：
11.4
通讯作者：
Riezman, H
中科院分区：
文献类型：
--
作者：
Zanolari, B;Friant, S;Riezman, H
酵母胞吞作用的内在化步骤需要肌动蛋白和固醇以获得最大效率。此外，许多受体和质膜蛋白必须在内化之前被磷酸化和泛素化。酿酒酵母end 8 -1突变体与lcb 1等位，lcb 1是一种在鞘氨醇碱合成的第一步中有缺陷的突变体。在类鞘氨醇碱合成停止后，可以看到胞吞作用的快速阻断。这种阻滞可以通过外源性鞘氨醇碱来克服。在内源性鞘氨醇碱合成被阻断且外源性鞘氨醇碱不能转化为磷酸化鞘氨醇碱或神经酰胺的条件下，鞘氨醇碱仍然可以抑制内吞缺陷。因此，所需的脂质很可能是鞘氨醇碱。有趣的是，类鞘氨醇碱的合成是肌动蛋白组织所必需的，但不是受体磷酸化所必需的。这是第一例鞘氨醇碱合成的生理作用，而不是作为神经酰胺或磷酸化鞘氨醇碱合成的前体。
The internalization step of endocytosis in yeast requires actin and sterols for maximum efficiency. In addition, many receptors and plasma membrane proteins must be phosphorylated and ubiquitylated prior to internalization. The Saccharomyces cerevisiae end8-1 mutant is allelic to lcb1, a mutant defective in the first step of sphingoid base synthesis. Upon arrest of sphingoid base synthesis a rapid block in endocytosis is seen. This block can be overcome by exogenous sphingoid base. Under conditions where endogenous sphingosine base synthesis was blocked and exogenous sphingoid bases could not be converted to phosphorylated sphingoid bases or to ceramide, sphingoid bases could still suppress the endocytic defect. Therefore, the required lipid is most likely a sphingoid base. Interestingly, sphingoid base synthesis is required for proper actin organization, but is not required for receptor phosphorylation. This is the first case of a physiological role for sphingoid base synthesis, other than as a precursor for ceramide or phosphorylated sphingoid base synthesis.