Proszynski Tomasz J, Klemm Robin, Bagnat Michel, Gaus Katharina, Simons Kai
Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
J Cell Biol. 2006 Jun 19;173(6):861-6. doi: 10.1083/jcb.200602007. Epub 2006 Jun 12.
The yeast mating cell provides a simple paradigm for analyzing mechanisms underlying the generation of surface polarity. Endocytic recycling and slow diffusion on the plasma membrane were shown to facilitate polarized surface distribution of Snc1p (Valdez-Taubas, J., and H.R. Pelham. 2003. Curr. Biol. 13:1636-1640). Here, we found that polarization of Fus1p, a raft-associated type I transmembrane protein involved in cell fusion, does not depend on endocytosis. Instead, Fus1p localization to the tip of the mating projection was determined by its cytosolic domain, which binds to peripheral proteins involved in mating tip polarization. Furthermore, we provide evidence that the lipid bilayer at the mating projection is more condensed than the plasma membrane enclosing the cell body, and that sphingolipids are required for this lipid organization.
酵母交配细胞为分析表面极性产生的潜在机制提供了一个简单的范例。内吞循环和在质膜上的缓慢扩散被证明有助于Snc1p的极化表面分布（瓦尔迪兹 - 陶巴斯，J.，和H.R. 佩勒姆。2003年。《当代生物学》13:1636 - 1640）。在这里，我们发现Fus1p（一种参与细胞融合的筏相关I型跨膜蛋白）的极化不依赖于内吞作用。相反，Fus1p定位于交配突起的尖端是由其胞质结构域决定的，该结构域与参与交配尖端极化的外周蛋白结合。此外，我们提供的证据表明，交配突起处的脂质双层比包围细胞体的质膜更致密，并且鞘脂是这种脂质组织所必需的。
