The Anillin-Related Region of Bud4 Is the Major Functional Determinant for Bud4's Function in Septin Organization during Bud Growth and Axial Bud Site Selection in Budding Yeast
The Anillin-Related Region of Bud4 Is the Major Functional Determinant for Bud4's Function in Septin Organization during Bud Growth and Axial Bud Site Selection in Budding Yeast
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DOI：
10.1128/ec.00268-14
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发表时间：
2015-01
期刊：
影响因子：
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通讯作者：
Huan Wu;Jia-Ping Guo;Ya-Ting Zhou;Xiang-Dong Gao
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文献类型：
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作者：
Huan Wu;Jia-Ping Guo;Ya-Ting Zhou;Xiang-Dong Gao
摘要酿酒酵母的芳香素相关蛋白Bud4是轴向芽位选择所必需的，它将轴向标志连接到位于母芽颈的隔膜上。最近的研究表明，Bud4在胞质分裂过程中参与了Septin的组织。在这里，我们证明了BUD4也参与了细胞质分裂前的芽生长期间的隔素组织，因为BUD4Δshs1Δ细胞在18°C时显示出拉长的芽形态和缺陷的隔素组织，Bud4的过表达也影响了30°C下Shs1Δ细胞在芽生长期间的隔素组织。令人惊讶的是，我们发现在整个细胞周期中，Bud4的中心区单独定位于芽颈，而不像全长Bud4，它只在G2/M期定位于芽颈。我们确定与苯胺素相关的区域是第二个靶向结构域，它与中央区域合作，以实现适当的Septin结合。此外，在花蕾生长和芽位选择过程中，香草素相关区域可能在很大程度上介导BUD4‘S在隔膜组织中的作用。我们发现该区域与Bud3的C末端相互作用，并且这两个片段相互依赖以与间隔蛋白相关联。此外，与bu4Δ突变体一样，bud3Δ突变体与shs1Δ和cdc12-6突变体在隔素组织中存在遗传上的相互作用，这表明Bud4和Bud3在花蕾生长过程中可能在隔素组织中相互作用。这些观察结果为Bud4与Septins和Bud3的相互作用提供了新的见解。
ABSTRACT The anillin-related protein Bud4 of Saccharomyces cerevisiae is required for axial bud site selection by linking the axial landmark to the septins, which localize at the mother bud neck. Recent studies indicate that Bud4 plays a role in septin organization during cytokinesis. Here we show that Bud4 is also involved in septin organization during bud growth prior to cytokinesis, as bud4Δ shs1Δ cells displayed an elongated bud morphology and defective septin organization at 18°C. Bud4 overexpression also affected septin organization during bud growth in shs1Δ cells at 30°C. Bud4 was previously thought to associate with the septins via its central region, while the C-terminal anillin-related region was not involved in septin association. Surprisingly, we found that the central region of Bud4 alone targets to the bud neck throughout the cell cycle, unlike full-length Bud4, which localizes to the bud neck only during G2/M phase. We identified the anillin-related region to be a second targeting domain that cooperates with the central region for proper septin association. In addition, the anillin-related region could largely mediate Bud4's function in septin organization during bud growth and bud site selection. We show that this region interacts with the C terminus of Bud3 and the two segments depend on each other for association with the septins. Moreover, like the bud4Δ mutant, the bud3Δ mutant genetically interacts with shs1Δ and cdc12-6 mutants in septin organization, suggesting that Bud4 and Bud3 may cooperate in septin organization during bud growth. These observations provide new insights into the interaction of Bud4 with the septins and Bud3.