Vesicle formation and recycling in the secretory pathway - from yeast to higher plants

对酵母菌的研究：1）分析了Arf 1 GT3基因的ts等位基因，分离了多拷贝抑制子。我们认为不同的GEF和GAP以等位基因特异性的方式参与。2)我们证明了Rer 1 p是高尔基体中的一种分选受体，可以检索ER膜蛋白的一个子集。我们还鉴定了Rer 1 p的高尔基体定位信号，并表明它们与COPI组分相互作用。3)我们鉴定了Sec 12 p和Sec 71 p的ER定位信号。我们还结晶了Sec 12 p并分析了其三维结构。4)我们表明，麦角固醇是必不可少的色氨酸通透酶Tat 2 p的质膜的目标。5)在植物上的研究：1）将AtARF 1的显性负突变体导入植物细胞，发现AtARF 1的表达抑制ER-高尔基体的运输。2)我们鉴定了Ara 6和Ara 7作为Rab GT3家族的新成员，并表明它们在核内体中起作用。我们发现Ara 6具有不同于其他传统Rab GTP酶的独特功能。3)我们发现，拟南芥RMA 1，最初分离的酵母sec 15突变体的抑制，编码一种新的膜结合的泛素连接酶。4)我们发现，拟南芥植物液泡膜的γTIP-GFP可视化显示非常动态和复杂的结构。5)通过对拟南芥茎向重力性突变体的分析，我们证明了液泡的发生在植物的重力感应中起着非常重要的作用。

Studies on yeast :1) We analyzed ts alleles of Arf1 GTPase and isolated multicopy suppressors. We suggested that different GEFs and GAPs are involved in an allele-specific manner. 2) We demonstrated that Rer1p is a sorting receptor in the Golgi that retrieves a subset of ER membrane proteins. We also identified the Golgi-localization signals of Rer1p and showed that they interact with COPI components. 3) We identified ER-localization signals of Sec12p and Sec71p. We also crystalized Sec12p and analyzed its 3-D structure. 4) We showed that ergosterol is essential for targeting of the tryptophan permease Tat2p to the plasma membrane. 5) We demonstrated that both Rer2p and its homologue Srt1p have the cis-prenyltransferase activity but show different characteristics.Studies on plants :1) We introduced dominant negative mutants of AtARF1 into plant cells and showed that its expression inhibits ER-Golgi traffic. 2) We identified Ara6 and Ara7 as new members of the Rab GTPase family and showed that they function in endosomes. We showed that Ara6 has uniques features distinct from other conventional Rab GTPases. 3) We showed that Arabidopsis RMA1, originally isolated as a suppressor of the yeast sec15 mutant, encodes a novel membrane-bound ubiquitin ligase. 4) We showed that vacuole membranes of Arabidopsis plants as visualized by γTIP-GFP display very dynamic and complex structures. 5) We demonstrated from the analysis of Arabidopsis shoot gravitropism mutants that vacuole biogenesis plays very important roles in the sensing of the gravity.