Toward understanding the molecular mechanisms that regulate intermediate filament keratin functions in hepatocytes

了解调节肝细胞中中间丝角蛋白功能的分子机制

• 批准号: 195539-2011
• 负责人: Cadrin, Monique
• 金额: $ 2.19万
• 依托单位: Université du Québec à Trois-Rivières
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569822
• 关键词: Toward; understanding; molecular; mechanisms; regulate

Intermediate filaments (IFs) are with microtubules and actin microfilaments the major cytoskeletal components of most mammalian cells. Modifications in K8/18 IFs organization and formation of keratin containing aggregates called Mallory-Denk bodies are common to many human chronic liver diseases such as alcoholic hepatitis, Wilson's disease and liver steatosis in obesity. Recent studies have shown evidences that K8/18 play an important role in the protection of hepatocytes against chronic stress-induced liver injuries. The long-term objective of our project is to determine the molecular mechanism by which K8/18 accomplish their protective role in hepatocytes. More specifically we want to test the hypothesis that K8/18 act as a key regulator in maintaining the delicate balance between pro and anti-apoptotic signals molecules. The short term objective of this proposal is to 1) perform a functional study to directly asses the role of keratins in the anti-apoptotic pathway PI3K/Akt. We will determine how modulation of K8/18 dynamic (expression, phosphorylation on specific sites) affects Akt pathway during the response of cell to Fas and TNF induced apoptosis. 2) There is accumulating evidence that sites and pattern- specific phosphorylation of keratin play a key role in the protection of hepatocytes against stress. Thus, we want to characterize by a proteomic approach the phosphorylation patterns of K8/18 in control hepatocytes and in hepatocytes from mice treated with the hepatotoxic drug griseofulvin. This study will be followed by a functional analysis of the specific K8/18 phosphorylation combination. The characterization of the signaling pathway in which keratins are involved and the study of the modifications that affect keratins (post-translational modification, association with other proteins) during the response of hepatocytes to apoptotic signal will constitute an important step in our understanding of the molecular mechanisms by which keratins accomplish their functions. This will directly lead us to further research on the cross-talk between keratins and cell signaling, and on how keratins affect disease pathogenesis.

中间丝（IFs）与微管和肌动蛋白微丝是大多数哺乳动物细胞的主要细胞骨架组成部分。K8/18 IF组织的修饰和称为Mallory-Denk小体的含角蛋白聚集体的形成在许多人类慢性肝病中是常见的，例如酒精性肝炎、威尔逊病和肥胖症中的肝脂肪变性。最近的研究表明，K8/18在肝细胞抗慢性应激性肝损伤中发挥重要作用。 我们项目的长期目标是确定K8/18在肝细胞中发挥保护作用的分子机制。更具体地说，我们想测试K8/18作为维持促凋亡和抗凋亡信号分子之间微妙平衡的关键调节因子的假设。该提案的短期目标是1）进行功能研究以直接评估角蛋白在抗凋亡途径PI 3 K/Akt中的作用。我们将确定在细胞对Fas和TNF诱导的凋亡的应答过程中，K8/18动态（表达，特定位点的磷酸化）的调节如何影响Akt通路。2)越来越多的证据表明，角蛋白的位点特异性磷酸化和模式特异性磷酸化在保护肝细胞对抗应激中起关键作用。因此，我们希望通过蛋白质组学方法来表征对照肝细胞和用肝毒性药物灰黄霉素治疗的小鼠肝细胞中K8/18的磷酸化模式。本研究之后将进行特异性K8/18磷酸化组合的功能分析。 角蛋白参与的信号通路的表征以及在肝细胞对凋亡信号的响应期间影响角蛋白的修饰（翻译后修饰，与其他蛋白质的结合）的研究将构成我们理解角蛋白实现其功能的分子机制的重要一步。这将直接引导我们进一步研究角蛋白与细胞信号传导之间的相互作用，以及角蛋白如何影响疾病的发病机制。