Regulation of transcriptional coactivator p300 by posttranslational modification

通过翻译后修饰调节转录辅激活因子 p300

• 批准号: RGPIN-2017-03734
• 负责人: Li, Qiao
• 金额: $ 2.91万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=657491
• 关键词: Regulation; transcriptional; coactivator; p300; posttranslational

The transcriptional coactivator p300 possess an intrinsic histone acetyltransferase (HAT) activity and is important for many cellular processes. A tight control of p300 is therefore critical to ensure locus-specific histone acetylation and gene regulation. We have established previously that p300 is dynamically regulated by posttranslational modification and distinct cellular distribution. We are the first to show that p300 is modulated by the cytoplasmic proteasome system. In addition, we have established that Akt/protein kinase B is a positive regulator of p300, while the B56γ3 regulatory subunit of protein phosphatase 2A (PP2A) is a negative regulator. Our works have provided novel insights into how cellular trafficking and spatial redistribution control the protein stability and transcriptional activity of p300. Recently, we found that p300 is regulated in a lineage specific manner during myogenic differentiation. As such, we intend to leverage our findings to define the molecular mechanisms underlying lineage-specific p300 regulation associated with myoblast differentiation. ******We hypothesize that reversible phosphorylaton plays critical roles in the control of p300 activity, which in turn modulates p300 function during myoblast differentiation, and propose to define the functional interactions of the B56γ3 regulatory subunit, Akt, and additional kinases with p300, in milieu of myoblast differentiation. We will survey p300 phosphorylation profiles and delineate the regulation of p300 by reversible phosphorylation with gain- and loss-of-function approaches. We will generate mutants that mimic candidate site phosphorylation and produce antibodies against site-specific phosphorylation to study the impact of reversible phosphorylation on p300 stability and transcriptional activity. Our goals are to determine the molecular basis for posttranslational modification-mediated p300 regulation and their consequences on the function of p300 as a HAT, a scaffold or a bridge on chromatin with respect to gene transcription. We will define the molecular mechanisms underlying different signaling pathways and p300 regulation pertinent to cellular differentiation. Our long term goals are to determine how these regulatory mechanisms control p300-dependent gene expression from intracellular trafficking, protein turnover to transcriptional activation, and to determine the molecular basis for p300 function in a network biology fashion. ******This research program is founded upon our recent findings and anchored on the p300 which is essential for different cellular processes and skeletal myogenesis in vivo. Many HQP will be trained through the proposed research as shown by our proven track record, and as a result, they will be well equipped to navigate into their own career path successfully and to contribute to our research field and different Canadian organizations significantly.

转录辅激活因子p300具有内在的组蛋白乙酰转移酶（HAT）活性，并且对于许多细胞过程是重要的。 因此，对p300的严格控制对于确保基因座特异性组蛋白乙酰化和基因调控至关重要。 我们以前已经建立了p300是动态调节的翻译后修饰和不同的细胞分布。 我们是第一个表明，p300是由细胞质蛋白酶体系统调制。 此外，我们已经确定Akt/蛋白激酶B是p300的正调节因子，而蛋白磷酸酶2A（PP 2A）的B56γ3调节亚基是负调节因子。 我们的工作提供了新的见解，细胞运输和空间再分布控制蛋白质的稳定性和转录活性的p300。 最近，我们发现，p300的调控在一个谱系特异性的方式在肌分化。 因此，我们打算利用我们的研究结果来确定与成肌细胞分化相关的谱系特异性p300调控的分子机制。 ** 我们假设可逆磷酸化在控制p300活性中起关键作用，p300活性反过来调节成肌细胞分化过程中p300的功能，并提出在成肌细胞分化的环境中确定B56γ3调节亚基Akt和其他激酶与p300的功能相互作用。 我们将调查p300的磷酸化概况，并描绘了可逆的磷酸化与增益和功能丧失的方法调节p300。 我们将产生模拟候选位点磷酸化的突变体，并产生针对位点特异性磷酸化的抗体，以研究可逆磷酸化对p300稳定性和转录活性的影响。 我们的目标是确定翻译后修饰介导的p300调控的分子基础及其对p300作为HAT，支架或染色质上的桥梁基因转录功能的影响。 我们将定义不同的信号通路和p300调节相关的细胞分化的分子机制。 我们的长期目标是确定这些调控机制如何控制p300依赖的基因表达，从细胞内运输，蛋白质周转到转录激活，并确定p300功能的分子基础，在网络生物学的时尚。** 这项研究计划是建立在我们最近的发现和锚定的p300是必不可少的不同的细胞过程和骨骼肌在体内的发生。 许多HQP将通过拟议的研究进行培训，正如我们已证明的记录所示，因此，他们将能够成功地进入自己的职业道路，并为我们的研究领域和不同的加拿大组织做出重大贡献。