Intracellular sphingolipid sorting drives membrane phase separation in the yeast vacuole.
Intracellular sphingolipid sorting drives membrane phase separation in the yeast vacuole.
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DOI：
10.1016/j.jbc.2023.105496
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发表时间：
2024-01
影响因子：
4.8
通讯作者：
Budin, Itay
中科院分区：
文献类型：
--
作者：
Kim, Hyesoo;Budin, Itay
酵母空泡膜可以相分离成有序和无序的结构域，这是营养限制下微噬脂所需的现象。尽管它作为一个生物物理模型和生理意义的重要性，它还没有解决，如果特定的脂质体的变化驱动空泡相分离。在这里，我们报告说，鞘脂（SL）的代谢和他们的分类到液泡膜可以控制这一过程。我们首先开发了一种空泡分离方法，以确定早期稳定期细胞相分离开始期间脂质体的变化。我们发现，早期静止阶段的液泡定义的增加丰度的推定筏组件，包括40%的麦角固醇含量高，近3倍的富集复杂的SL（CSL）。在相应的全细胞脂质体中没有发现这些变化，表明脂质分选与结构域形成相关。SL组合物的几个方面-头基化学计量，较长的链长，和增加的羟基化-也是相分离的空泡脂质体的标记。为了测试SL在液泡相分离中的功能，我们对其生物合成途径进行了系统的遗传解剖。丰富的CSL控制域形成的程度和相关的micro-lipophagy过程，而它们的头基组合物改变域形态。这些结果表明，脂质运输可以在体内驱动膜相分离，并确定SL作为酵母中这一过程的关键介质。
The yeast vacuole membrane can phase separate into ordered and disordered domains, a phenomenon that is required for micro-lipophagy under nutrient limitation. Despite its importance as a biophysical model and physiological significance, it is not yet resolved if specific lipidome changes drive vacuole phase separation. Here we report that the metabolism of sphingolipids (SLs) and their sorting into the vacuole membrane can control this process. We first developed a vacuole isolation method to identify lipidome changes during the onset of phase separation in early stationary stage cells. We found that early stationary stage vacuoles are defined by an increased abundance of putative raft components, including 40% higher ergosterol content and a nearly 3-fold enrichment in complex SLs (CSLs). These changes were not found in the corresponding whole cell lipidomes, indicating that lipid sorting is associated with domain formation. Several facets of SL composition—headgroup stoichiometry, longer chain lengths, and increased hydroxylations—were also markers of phase-separated vacuole lipidomes. To test SL function in vacuole phase separation, we carried out a systematic genetic dissection of their biosynthetic pathway. The abundance of CSLs controlled the extent of domain formation and associated micro-lipophagy processes, while their headgroup composition altered domain morphology. These results suggest that lipid trafficking can drive membrane phase separation in vivo and identify SLs as key mediators of this process in yeast.