Association of yeast transporters with detergent-resistant membranes correlates with their cell-surface location
Association of yeast transporters with detergent-resistant membranes correlates with their cell-surface location
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DOI：
10.1111/j.1600-0854.2006.00445.x
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发表时间：
2006-08-01
期刊：
影响因子：
4.5
通讯作者：
Andre, Bruno
中科院分区：
文献类型：
--
作者：
Lauwers, Elsa;Andre, Bruno
富含麦角固醇和鞘脂的耐洗涤剂膜（DRM）组分可以从酵母细胞中分离出来，并被认为是脂筏的生化等价物。除了Hxt 1和Gap 1渗透酶外，大多数研究其去污剂溶解性的酵母质膜蛋白都存在于DRM中。我们在这里比较了Gap 1洗涤剂溶解性在野生型和各种突变体细胞的条件下，促进细胞表面积累或泛素依赖性下调的通透酶。我们发现，Gap 1目前在质膜与DRM。这种关联发生在高尔基体水平。在没有鞘脂新合成的情况下，Gap 1不能在质膜上积累，并且被错误地分选到液泡腔中。此外，Gap 1在质膜上的存在与其与DRM的关联完全相关，无论通透酶的活性或泛素化状态如何，也无论它是否通过正常分泌、再循环后或在重新路由到质膜之前错误分选到液泡后到达细胞表面。最后，我们表明，Hxt 1目前在细胞表面也与DRM。我们讨论了一个模型，其中酵母质膜蛋白系统地与鞘脂/麦角甾醇富集的微结构域位于细胞表面时。
Detergent-resistant membrane (DRM) fractions enriched in ergosterol and sphingolipids can be isolated from yeast cells and have been proposed to represent the biochemical equivalents of lipid rafts. Most yeast plasma membrane proteins studied for their detergent solubility have been found in DRMs, except for the Hxt1 and Gap1 permeases. We here compared Gap1 detergent solubility in wild-type and various mutant cells under conditions promoting cell surface accumulation or ubiquitin-dependent down-regulation of the permease. We show that Gap1 present at the plasma membrane is associated with DRMs. This association occurs at the Golgi level. In the absence of sphingolipid neosynthesis, Gap1 fails to accumulate at the plasma membrane and is missorted to the vacuolar lumen. Furthermore, the presence of Gap1 at the plasma membrane correlates perfectly with its association with DRMs, whatever the activity or ubiquitination state of the permease and regardless of whether it has reached the cell surface via normal secretion, after recycling, or upon missorting to the vacuole before rerouting to the plasma membrane. Finally, we show that Hxt1 present at the cell surface is also associated with DRMs. We discuss a model where yeast plasma membrane proteins are systematically associated with sphingolipid/ergosterol-enriched microdomains when located at the cell surface.