Cdk5 regulation of calcium dynamics

Cdk5 钙动力学调节

• 批准号: RGPIN-2019-06270
• 负责人: Lee, KiYoung
• 金额: $ 2.33万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=746559
• 关键词: Cdk5; regulation; calcium; dynamics

The general interest of our laboratory is to understand how protein kinases regulate specialized cell functions. We focus on cyclin-dependent kinases (Cdks) in general and Cdk5 in particular. Cdk5 is a serine/threonine kinase that has been strongly implicated in mammalian development, and thus, our long-term objective is to uncover the fundamental molecular and cellular mechanisms of Cdk5 regulation and function. Throughout our over two decades of Cdk5 studies, we have demonstrated that Cdk5 activity is regulated by specific protein activators and that Cdk5 interactions serve to enhance or inhibit diverse cellular functions. Our research breakthroughs define the basic roles and significance of Cdk5 in gene expression, cell differentiation and secretion among others. Our recent studies point to Cdk5 as a regulator of calcium (Ca2+) dynamics and cell proliferation. By taking advantage of the Cdk5-/- knockout and mouse embryonic fibroblast (MEF) model systems, we found that Cdk5-/- MEFs proliferate at a faster rate compared to wt. We further found greater ATP-induced IP3R-mediated Ca2+ release from the endoplasmic reticulum (ER) in Cdk5-/- MEFs. Since we found that Cdk5 interacts with IP3R, and IP3R type 1 has two potential Cdk5 phosphorylation sites, our premise is that Cdk5 controls IP3R1-mediated Ca2+ release from the ER, possibly through IP3R1 phosphorylation. Our data suggest that Cdk5 control of ER Ca2+ release limits Ca2+ influx into mitochondria. Because mitochondrial Ca2+ uptake is associated with transient mPTP opening and production of ROS, which promotes cell proliferation, our view is that Cdk5 controls ER-mitochondria Ca2+ crosstalk, regulating mitochondrial Ca2+ concentration ([Ca2+]m), transient mPTP opening and ROS level, and subsequently, cell proliferation. Indeed, Ca2+ is key to signal transduction pathways leading to different cellular activities, and it is possible that Cdk5-regulated Ca2+ dynamics accounts for Cdk5-regulated cell proliferation. Thus, in line with our general hypothesis that Cdk5 is key to an elaborate system of protein-protein interactions and phosphorylation events that modulate specific cellular processes, and our short-term goal of understanding the connections between Cdk5-controlled Ca2+dynamics and Cdk5-regulated cell proliferation, our specific aims are: (i) to examine Cdk5 regulation of the IP3R-mediated Ca2+ signaling pathway, and (ii) to investigate Cdk5 involvement in Ca2+-regulated, mitochondria-mediated functions. Our proposed research will (i) generate new and significant knowledge on Cdk5 and its fundamental role in controlling Ca2+ dynamics and cell proliferation, which will (ii) serve as foundation for our next steps in our program that aims to elucidate the importance of Cdk5 in mammalian development, and (iii) elevate the status of two HQP, who will dedicate 100% of their time on our research program, which will serve as their channels for training and development.

我们实验室的主要兴趣是了解蛋白激酶如何调节专门的细胞功能。我们专注于细胞周期蛋白依赖性激酶（Cdks）一般，特别是Cdk 5。Cdk 5是一种丝氨酸/苏氨酸激酶，与哺乳动物的发育密切相关，因此，我们的长期目标是揭示Cdk 5调控和功能的基本分子和细胞机制。在我们二十多年的Cdk 5研究中，我们已经证明Cdk 5活性受特定蛋白激活剂的调节，并且Cdk 5相互作用有助于增强或抑制多种细胞功能。我们的研究突破定义了Cdk 5在基因表达，细胞分化和分泌等方面的基本作用和意义。我们最近的研究指出Cdk 5作为钙（Ca 2+）动力学和细胞增殖的调节剂。通过利用Cdk 5-/-敲除和小鼠胚胎成纤维细胞（MEF）模型系统，我们发现Cdk 5-/-MEF与wt.我们进一步发现，更大的ATP诱导的IP 3R介导的Ca 2+释放内质网（ER）在Cdk 5-/- MEFs。由于我们发现Cdk 5与IP 3R相互作用，并且IP 3R 1型具有两个潜在的Cdk 5磷酸化位点，因此我们的前提是Cdk 5可能通过IP 3R 1磷酸化控制IP 3R 1介导的Ca 2+从ER释放。我们的数据表明，Cdk 5控制ER Ca 2+释放限制Ca 2+流入线粒体。由于线粒体Ca 2+摄取与瞬时mPTP开放和ROS产生相关，从而促进细胞增殖，因此我们认为Cdk 5控制ER-线粒体Ca 2+串扰，调节线粒体Ca 2+浓度（[Ca 2 +]m）、瞬时mPTP开放和ROS水平，并随后调节细胞增殖。事实上，Ca 2+是导致不同细胞活性的信号转导途径的关键，并且Cdk 5调节的Ca 2+动力学可能是Cdk 5调节的细胞增殖的原因。因此，根据我们的一般假设，Cdk 5是调节特定细胞过程的蛋白质-蛋白质相互作用和磷酸化事件的复杂系统的关键，以及我们理解Cdk 5控制的Ca 2+动力学和Cdk 5调节的细胞增殖之间的联系的短期目标，我们的具体目标是：（i）检查Cdk 5对IP 3R介导的Ca 2+信号传导途径的调节，和（ii）研究Cdk 5参与Ca 2+调节，我们提出的研究将（i）产生关于Cdk 5及其在控制Ca 2+中的基本作用的新的重要知识动力学和细胞增殖，这将（ii）作为我们计划的下一步的基础，旨在阐明Cdk 5在哺乳动物发育中的重要性，以及（iii）提升两名HQP的地位，他们将把100%的时间投入到我们的研究计划中，这将作为他们的培训和发展渠道。