Department of Biology/Chemistry Bioanalytical Chemistry Section, Osnabrück University , Osnabrück, Germany.
Department of Biochemistry and Molecular Biology Villum Center for Bioanalytical Sciences, University of Southern Denmark , Odense, Denmark.
J Cell Biol. 2023 May 1;222(5). doi: 10.1083/jcb.202109162. Epub 2023 Mar 10.
Ceramides are essential precursors of complex sphingolipids and act as potent signaling molecules. Ceramides are synthesized in the endoplasmic reticulum (ER) and receive their head-groups in the Golgi apparatus, yielding complex sphingolipids (SPs). Transport of ceramides between the ER and the Golgi is executed by the essential ceramide transport protein (CERT) in mammalian cells. However, yeast cells lack a CERT homolog, and the mechanism of ER to Golgi ceramide transport remains largely elusive. Here, we identified a role for yeast Svf1 in ceramide transport between the ER and the Golgi. Svf1 is dynamically targeted to membranes via an N-terminal amphipathic helix (AH). Svf1 binds ceramide via a hydrophobic binding pocket that is located in between two lipocalin domains. We showed that Svf1 membrane-targeting is important to maintain flux of ceramides into complex SPs. Together, our results show that Svf1 is a ceramide binding protein that contributes to sphingolipid metabolism at Golgi compartments.
神经酰胺是复杂鞘脂类的必需前体，也是有效的信号分子。神经酰胺在内质网（ER）中合成，并在高尔基器中接收其头部基团，从而产生复杂的鞘脂类（SPs）。在哺乳动物细胞中，神经酰胺通过必需的神经酰胺转运蛋白（CERT）在 ER 和高尔基体之间运输。然而，酵母细胞缺乏 CERT 同源物，ER 到高尔基体的神经酰胺运输机制在很大程度上仍不清楚。在这里，我们确定了酵母 Svf1 在 ER 和高尔基体之间神经酰胺运输中的作用。Svf1 通过 N 端的两亲性螺旋（AH）动态靶向膜。Svf1 通过位于两个亲脂素结构域之间的疏水结合口袋与神经酰胺结合。我们表明，Svf1 膜靶向对于维持神经酰胺进入复杂 SPs 的通量很重要。总之，我们的结果表明，Svf1 是一种神经酰胺结合蛋白，它有助于高尔基隔室中的鞘脂代谢。
