Role of Tuberin in Mitotic Progression

马铃薯蛋白在有丝分裂进展中的作用

• 批准号: RGPIN-2014-06636
• 负责人: Porter, Lisa
• 金额: $ 3.42万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567941
• 关键词: Role; Tuberin; Mitotic; Progression

A great deal of ground breaking work has determined that the Tuberin and Hamartin complex function as a negative regulator of protein synthesis and cell cycle progression through G1/S. This is largely attributed to the GTPase activity of Tuberin functioning to indirectly inhibit the mammalian target of rapamycin (mTOR). While current work on this pathway is focused on the regulation of G1/S, there is significant evidence which points to a potential role for the Tuberin-Hamartin complex in G2/M regulation. Data from our NSERC program has characterized a direct interaction between Tuberin and the mitotic cyclin, Cyclin B1. We have mapped the Cyclin B1 binding sites in Tuberin and have shown that functionally this interaction delays the shuttling of Cyclin B1 to the nucleus, and subsequent mitotic onset. Interestingly, we have demonstrated that in the absence of nutrients and/or Akt phosphorylation of Tuberin the Tuberin-Cyclin B1 interaction is reduced and cells enter mitosis. This raises the exciting possibility that Tuberin regulates a novel cell cycle checkpoint linking mitotic onset with the nutritional status of the cell. Resolving the molecular mechanism by which Tuberin and Cyclin B1 interact, and the consequences of this on cell cycle regulation and overall cell physiology are the focus of this research program. Hypothesis: A direct interaction between Tuberin and Cyclin B1 constitutes a key component of a novel cell cycle checkpoint whereby initiation of mitosis is linked to the external growth conditions of the cell. This checkpoint functions in part to regulate cell size and differentiation decisions in the presence of specific growth/differentiation factors and nutrients. Short-term objectives: Using a number of key technologies that we have established in our lab over the past grant period we will: 1. dissect the dynamics of the Cyclin B1-Ck1 interaction with Tuberin-Hamartin. 2. determine whether the Cyclin B1-Tuberin interaction constitutes a cell size checkpoint and whether this is involved in differentiation decisions. 3. address the importance of nuclear accumulation of Tuberin during mitosis. Long term objectives: To study specific Tuberin mutations in animal model systems to address the physiological consequence of this checkpoint in system development, maintenance and response to a number of different stressors. Our data has revealed a novel and exciting regulatory mechanism controlling the onset of mitosis. This research program seeks to resolve the molecular complexities and the cellular consequences of this interaction; data which is essential for understanding normal cell growth mechanisms.

大量的开创性工作已经确定，在蛋白质合成和细胞周期的G1/S进程中，Hamartin和residin复合物作为负调节剂发挥作用。这在很大程度上归因于具有间接抑制雷帕霉素哺乳动物靶标（mTOR）功能的雷帕霉素的GTclase活性。虽然目前对这一途径的研究主要集中在G1/S的调控上，但有重要证据表明，在G2/M调控中，β-胡萝卜素-Hamartin复合物具有潜在的作用。来自我们的NSERC计划的数据已经表征了细胞周期蛋白和有丝分裂细胞周期蛋白，细胞周期蛋白B1之间的直接相互作用。我们已经绘制了细胞周期蛋白B1的结合位点，并已表明，在功能上，这种相互作用延迟穿梭细胞周期蛋白B1的细胞核，随后有丝分裂的开始。有趣的是，我们已经证明，在缺乏营养素和/或Akt的磷酸化，在细胞周期蛋白B1的相互作用中，细胞周期蛋白B1的减少和细胞进入有丝分裂。这提出了一个令人兴奋的可能性，即Escherin调节一种新的细胞周期检查点，将有丝分裂的开始与细胞的营养状态联系起来。解决的分子机制，通过它和细胞周期蛋白B1相互作用，以及这对细胞周期调控和整体细胞生理学的后果是这个研究计划的重点。假设：细胞周期蛋白B1和细胞周期蛋白B1之间的直接相互作用构成了一个新的细胞周期检查点的关键组成部分，有丝分裂的启动与细胞的外部生长条件有关。在特定生长/分化因子和营养物的存在下，该检查点部分地起到调节细胞大小和分化决定的作用。短期目标：利用我们在过去的资助期内在实验室建立的一些关键技术，我们将：1。剖析细胞周期蛋白B1-Ck 1相互作用的动力学与heparin-Hamartin。2.确定细胞周期蛋白B1-β蛋白相互作用是否构成细胞大小检查点，以及这是否参与分化决定。3.解决了有丝分裂过程中的细胞核积累的重要性。长期目标：在动物模型系统中研究特定的tetrain突变，以解决该检查点在系统发育、维持和对许多不同压力源的反应中的生理后果。我们的数据揭示了一个新的和令人兴奋的调控机制控制有丝分裂的开始。该研究计划旨在解决这种相互作用的分子复杂性和细胞后果;数据对于理解正常细胞生长机制至关重要。