Genetic and functional interaction between Ryh1 and Ypt3:: two Rab GTPases that function in S-pombe secretory pathway
Genetic and functional interaction between Ryh1 and Ypt3:: two Rab GTPases that function in S-pombe secretory pathway
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DOI：
10.1111/j.1365-2443.2006.00935.x
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发表时间：
2006-03-01
期刊：
影响因子：
2.1
通讯作者：
Kuno, T
中科院分区：
文献类型：
--
作者：
He, Y;Sugiura, R;Kuno, T
我们之前分离出了 ypt3-i5 突变体，并表明 Ypt3 GTPase 在裂殖酵母分泌途径中发挥作用。在这里，相同的遗传筛选导致了 ryh1-i6 的分离，这是编码 Rab6 同源物的 ryh1(+) 基因的突变等位基因。 ryh1-i6 突变体表现出的表型支持其在从内体到高尔基体的逆行运输中的作用。有趣的是，ryh1(+) 基因缺失对于 ypt3-i5 突变具有综合致死性。一致地，GDP构象突变体Ryh1T25 N的过度表达抑制了ypt3-i5突变体的生长，但对野生型细胞的生长没有影响。此外，Ryh1T25N突变体的过表达抑制了ypt3-i5突变体的酸性磷酸酶糖基化并加剧了细胞壁的完整性，但对野生型细胞没有影响。 GFP-Ryh1 和 GFP-Ypt3 均定位于高尔基体/内体，但显示出不同的亚细胞定位。 GFP-Ryh1 在 ypt3-i5 突变体中的定位和 GFP-Ypt3 在 ryh1-i6 突变体中的定位与野生型细胞中的定位不同。此外，Ryh1 和 Ypt3 被证明参与酸性磷酸酶的分泌。这些结果表明，Ryh1 参与分泌途径，除了在回收中的作用外，还可能与 Ypt3 具有潜在的重叠功能。
We have previously isolated ypt3-i5 mutant and showed that Ypt3 GTPase functions in the fission yeast secretory pathway. Here, the same genetic screen led to the isolation of ryh1-i6, a mutant allele of the ryh1(+) gene encoding a homolog of Rab6. The ryh1-i6 mutant showed phenotypes that support its role in retrograde traffic from endosome to the Golgi. Interestingly, ryh1(+) gene deletion was synthetically lethal with ypt3-i5 mutation. Consistently, the over-expression of the GDP-conformational mutant, Ryh1T25 N, inhibited the growth of ypt3-i5 mutant but had no effect on that of wild-type cells. Furthermore, the over-expression of the Ryh1T25N mutant inhibited the acid phosphatase glycosylation and exacerbated the cell wall integrity of ypt3-i5 mutant, but had no effect on those of wild-type cells. GFP-Ryh1 and GFP-Ypt3 both localized at the Golgi/endosome, but showed distinct subcellular localizations. The localization of GFP-Ryh1 in ypt3-i5 mutant and that of GFP-Ypt3 in ryh1-i6 mutant were distinct from those in wild-type cells. In addition, Ryh1 as well as Ypt3 were shown to be involved in acid phosphatase secretion. These results suggest that Ryh1 is involved in the secretory pathway and may have a potential overlapping function with Ypt3 in addition to its role in recycling.