The Integrity of the Plant Golgi Apparatus Depends on Cell Growth-Controlled Activity of GNL1
The Integrity of the Plant Golgi Apparatus Depends on Cell Growth-Controlled Activity of GNL1
复制标题
DOI：
10.1093/mp/sss124
复制
发表时间：
2013-05-01
期刊：
影响因子：
27.5
通讯作者：
Brandizzi, Federica
中科院分区：
文献类型：
--
作者：
Du, Wenyan;Tamura, Kentaro;Brandizzi, Federica
膜运输依赖于ARF-GTP酶，其活性由鸟嘌呤-核苷酸交换因子（ARF-GEF）控制。在细胞生长过程中，ARF和ARF-GEFs的活性如何相互关联在很大程度上是未知的。这项工作表明，高尔基体交通的影响很大程度上是由已知的ARF-GEF GNL 1在子叶细胞扩张的早期阶段，但由布雷菲德菌素A敏感的GEFs细胞生长终止时。这些数据揭示了GNL 1生物学的一个未预料到的复杂性水平，表明其细胞作用与细胞生长相关。植物分泌途径中的膜运输和细胞器完整性依赖于ARF-GTP酶，其被鸟嘌呤-核苷酸交换因子（ARF-GEFs）激活。虽然少数植物ARF-GEF已显示出保守作用的维持、独特功能的进化以及组织特异性作用，但一个基本但尚未回答的问题是它们在细胞生长期间功能重叠的程度。为了解决这一问题，我们已经表征了pao，一种新的Gnom样1（GNL 1）等位基因，一种布雷菲德菌素A（BFA）不敏感的ARF-GEF，通过共聚焦显微镜为基础的正向遗传学筛选分离的高尔基体在拟南芥。具体而言，我们已经分析了依赖的完整性的运输路线和分泌细胞器上GNL 1的可用性在子叶表皮细胞，一个精致的模型系统，在完整的组织中的营养细胞生长分析的扩展阶段。我们发现，高尔基体交通的影响很大程度上是由GNL 1在子叶细胞扩张的早期阶段，但由BFA敏感的GEFs细胞生长终止时的可用性。这些数据揭示了GNL 1生物学中意想不到的复杂程度，表明其细胞作用与细胞生长相关。这些结果还表明，细胞生长阶段是ARF-GEF细胞作用功能分析的重要因素。
Membrane traffic depends on ARF-GTPases whose activity is controlled by guanine-nucleotide exchange factors (ARF-GEFs). How the activity of ARFs and ARF-GEFs is correlated during cell growth is largely unknown. This work demonstrates that Golgi traffic is influenced largely by the known ARF-GEF GNL1 at early stages of cotyledon cell expansion but by brefeldin A-sensitive GEFs when cell growth terminates. These data reveal an unanticipated level of complexity in the biology of GNL1 by showing that its cellular roles are correlated with cell growth.Membrane traffic and organelle integrity in the plant secretory pathway depend on ARF-GTPases, which are activated by guanine-nucleotide exchange factors (ARF-GEFs). While maintenance of conserved roles, evolution of unique functions as well as tissue-specific roles have been shown for a handful of plant ARF-GEFs, a fundamental yet unanswered question concerns the extent to which their function overlaps during cell growth. To address this, we have characterized pao, a novel allele of GNOM-like 1 (GNL1), a brefeldin A (BFA)-insensitive ARF-GEF, isolated through a confocal microscopy-based forward genetics screen of the Golgi in Arabidopsis thaliana. Specifically, we have analyzed the dependence of the integrity of trafficking routes and secretory organelles on GNL1 availability during expansion stages of cotyledon epidermal cells, an exquisite model system for vegetative cell growth analyses in intact tissues. We show that Golgi traffic is influenced largely by GNL1 availability at early stages of cotyledon cell expansion but by BFA-sensitive GEFs when cell growth terminates. These data reveal an unanticipated level of complexity in the biology of GNL1 by showing that its cellular roles are correlated with cell growth. These results also indicate that the cell growth stage is an important element weighting into functional analyses of the cellular roles of ARF-GEFs.