Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
J Cell Biol. 2011 Nov 14;195(4):657-71. doi: 10.1083/jcb.201104045. Epub 2011 Nov 7.
Yeast is a powerful model organism for dissecting the temporal stages and choreography of the complex protein machinery during endocytosis. The only known mechanism for endocytosis in yeast is clathrin-mediated endocytosis, even though clathrin-independent endocytic pathways have been described in other eukaryotes. Here, we provide evidence for a clathrin-independent endocytic pathway in yeast. In cells lacking the clathrin-binding adaptor proteins Ent1, Ent2, Yap1801, and Yap1802, we identify a second endocytic pathway that depends on the GTPase Rho1, the downstream formin Bni1, and the Bni1 cofactors Bud6 and Spa2. This second pathway does not require components of the better-studied endocytic pathway, including clathrin and Arp2/3 complex activators. Thus, our results reveal the existence of a second pathway for endocytosis in yeast, which suggests similarities with the RhoA-dependent endocytic pathways of mammalian cells.
酵母是一种强大的模式生物，可用于剖析胞吞作用过程中复杂蛋白质机器的时间阶段和协调作用。酵母中唯一已知的胞吞作用机制是网格蛋白介导的胞吞作用，尽管在其他真核生物中已经描述了非网格蛋白依赖的胞吞作用途径。在这里，我们提供了酵母中存在非网格蛋白依赖的胞吞作用途径的证据。在缺乏网格蛋白结合衔接蛋白 Ent1、Ent2、Yap1801 和 Yap1802 的细胞中，我们鉴定出第二种依赖于 GTPase Rho1、下游成核因子 Bni1 以及 Bni1 共因子 Bud6 和 Spa2 的胞吞作用途径。第二种途径不需要更深入研究的胞吞作用途径的成分，包括网格蛋白和 Arp2/3 复合物激活剂。因此，我们的结果揭示了酵母中第二种胞吞作用途径的存在，这表明与哺乳动物细胞中 RhoA 依赖性胞吞作用途径存在相似性。
