Functional characterization and localization of the Aspergillus nidulans formin SEPA.
Functional characterization and localization of the Aspergillus nidulans formin SEPA.
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DOI：
10.1091/mbc.01-07-0356
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发表时间：
2002-02
影响因子：
3.3
通讯作者：
Kathryn E. Sharpless;S. Harris
中科院分区：
文献类型：
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作者：
Kathryn E. Sharpless;S. Harris
Formins是一个多结构域支架蛋白家族，参与肌动蛋白依赖的形态发生事件。在nidulans中，Forin SEPA参与了两个肌动蛋白介导的过程，即隔膜形成和极化生长。在这项研究中，我们使用一个新的零突变体来证明SEPA是在隔膜位置形成肌动蛋白环所必需的。此外，我们还发现有功能的SEPA：：GFP融合蛋白同时定位于隔膜部位和菌丝顶端，并且SEPA与肌动蛋白在每个部位共定位。通过实时成像，我们发现SEPA在间隔部位和菌丝尖端的定位是动态的。值得注意的是，在隔膜部位，SEPA形成一个环，随着隔膜的沉积而收缩。此外，我们证明了肌动蛋白细丝是维持SEPA正确定位模式所必需的，并且SEPA的氨基末端部分足以定位在隔膜位置和菌丝尖端。相反，只有分隔部位的定位受到Seph基因产物丢失的影响。我们认为，特定的形态线索激活了共同的分子途径，将SEPA定位到适当的形态发生部位。
Formins are a family of multidomain scaffold proteins involved in actin-dependent morphogenetic events. In Aspergillus nidulans, the formin SEPA participates in two actin-mediated processes, septum formation and polarized growth. In this study, we use a new null mutant to demonstrate that SEPA is required for the formation of actin rings at septation sites. In addition, we find that a functional SEPA::GFP fusion protein localizes simultaneously to septation sites and hyphal tips, and that SEPA colocalizes with actin at each site. Using live imaging, we show that SEPA localization at septation sites and hyphal tips is dynamic. Notably, at septation sites, SEPA forms a ring that constricts as the septum is deposited. Moreover, we demonstrate that actin filaments are required to maintain the proper localization pattern of SEPA, and that the amino-terminal half of SEPA is sufficient for localization at septation sites and hyphal tips. In contrast, only localization at septation sites is affected by loss of the sepH gene product. We propose that specific morphological cues activate common molecular pathways to direct SEPA localization to the appropriate morphogenetic site.