Estrada Alejandro F, Muruganandam Gopinath, Prescianotto-Baschong Cristina, Spang Anne
Growth & Development, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
Growth & Development, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
Biol Open. 2015 May 11;4(7):792-802. doi: 10.1242/bio.011528.
Proteins reach the plasma membrane through the secretory pathway in which the trans Golgi network (TGN) acts as a sorting station. Transport from the TGN to the plasma membrane is maintained by a number of different pathways that act either directly or via the endosomal system. Here we show that a subset of cargoes depends on the ArfGAP2/3 Glo3 and ergosterol to maintain their proper localization at the plasma membrane. While interfering with neither ArfGAP2/3 activity nor ergosterol biosynthesis individually significantly altered plasma membrane localization of the tryptophan transporter Tat2, the general amino acid permease Gap1 and the v-SNARE Snc1, in a Δglo3 Δerg3 strain those proteins accumulated in internal endosomal structures. Export from the TGN to the plasma membrane and recycling from early endosomes appeared unaffected as the chitin synthase Chs3 that travels along these routes was localized normally. Our data indicate that a subset of proteins can reach the plasma membrane efficiently but after endocytosis becomes trapped in endosomal structures. Our study supports a role for ArfGAP2/3 in recycling from endosomes and in transport to the vacuole/lysosome.
蛋白质通过分泌途径到达质膜，其中反式高尔基体网络（TGN）充当分拣站。从TGN到质膜的运输由许多不同的途径维持，这些途径要么直接起作用，要么通过内体系统起作用。在这里，我们表明一部分货物依赖于ArfGAP2/3 Glo3和麦角固醇来维持它们在质膜上的正确定位。虽然单独干扰ArfGAP2/3活性或麦角固醇生物合成都不会显著改变色氨酸转运蛋白Tat2、通用氨基酸通透酶Gap1和v-SNARE Snc1在质膜上的定位，但在Δglo3Δerg3菌株中，这些蛋白质在内体内部结构中积累。由于沿着这些途径运输的几丁质合酶Chs3定位正常，从TGN到质膜的输出以及从早期内体的回收似乎未受影响。我们的数据表明，一部分蛋白质可以有效地到达质膜，但在胞吞作用后会被困在内体结构中。我们的研究支持ArfGAP2/3在从内体回收以及运输到液泡/溶酶体中的作用。
