CYTOSKELETAL PROTEIN PHOSPHORYLATION IN APOPTOSIS

细胞凋亡中的细胞骨架蛋白磷酸化

• 批准号: 6454822
• 负责人: Gail V. W. Johnson
• 金额: $ 5万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6454822
• 关键词: Alzheimer's disease; PC12 cells; Parkinson's disease; apoptosis; cell cycle proteins; confocal scanning microscopy; cytoskeleton; gene expression; gene mutation; immunocytochemistry; intermolecular interaction; matrix assisted laser desorption ionization; microtubules; molecular pathology; molecular site; neural degeneration; neurofibrillary tangles; neuropathology; paired helical filament; phosphoproteins; phosphorylation; protein kinase; protein localization; protein structure function; tau proteins

DESCRIPTION: (Verbatim from the Applicant's Abstract) During apoptosis the cytoskeleton of the cell undergoes dynamic alterations which result in the characterisitic morphological changes common to most apoptotic cells. Recently, using the classical paradigm of inducing apoptosis differentiated PC12 cells by withdrawal of serum and nerve growth factor (NGF), we demonstrated that the neuronal cytoskeletal protein tau is hyperphosphorylated at specific epitopes during apoptosis. Further, there are associated functional changes, as the microtubule-bindng capacity of tau from apoptotic cells is significantly reduced, and it is restored after dephosphorylation. This demonstrates directly that the increased phosphorylation of tau in cells undergoing apoptosis impairs the function of tau, and thus may contribute to the microtubule instability and the cytoskeletal based morphological changes of apoptotic cells. These findings are exciting both for the insight they provide for understanding the drastic morphological changes associated with apoptosis, and for the potential links between apoptosis in Alzheimer's disease and hyperphosphorylated tau. There is increasing evidence that apoptotic-like processes may contribute to the neuronal death in Alzheimer's disease, as well as other neurodegenerative disorders. In Alzheimer's disease brain, extensively hyperphosphorylated tau forms paired helical filaments (PHFs). In addition, the microtubule binding of PHF-tau is impaired, but can be restored at least partially by dephosphorylation. Thus, apoptosis during Alzheimer's disease may contribute to the formation of hyperphosphorylated tau that accumulated in this disease, thereby further emphasising the need to clarify the mechanisms that control tau phosphorylation in these conditions. In AD brain, cdc2, casein kinase1d (CK1d ) and cdk5 are elevated, and the investigators have found them to be increased during apoptosis as well. Considering these and other findings, the comprehensive working hypothesis is that during apoptosis tau is hyperphosphorylated at specific sites by specific protein kinases and this hyperphosphorylation results in compromised tau function, which contributes to the structural changes that occur during apoptosis. Elucidation of the changes in tau phosphorylation that occur during apoptosis will contribute towards the understanding of the processes that result in the hyperphosphorylation of tau in AD and other neurodegenerative disorders. The specific aims of this proposal are to test the hypotheses that: (1) during apoptosis tau is phosphorylated at specific sites and the increases in the activities of cdc2, CK1d and cdk5 are essential components of this process, (2) that the specific sites on tau that are phosphorylated in apoptotic cells modulate tau function and localization, and (3) that during apoptosis, tau with frontal temporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17) mutations is differentially phosporylated and localized compared to wild type tau.

描述：（申请人的摘要的逐字化）在凋亡期间 细胞的细胞骨架经历动态改变，导致 大多数凋亡细胞常见的特征形态变化。最近， 使用诱导凋亡的经典范式通过 戒断血清和神经生长因子（NGF），我们证明了 神经元细胞骨架蛋白tau在特定表位上被过度磷酸化 在凋亡期间。此外，有相关的功能变化，因为 来自凋亡细胞的tau的微管结合能力显着 减少，并在去磷酸化后恢复。这直接演示 在经历凋亡损害的细胞中Tau的磷酸化增加的增加 tau的功能，因此可能有助于微管的不稳定和 基于细胞骨架的凋亡细胞的形态变化。这些发现 对于他们提供的洞察力而令人兴奋 与凋亡相关的形态变化以及潜在的联系 在阿尔茨海默氏病的凋亡与高磷酸化的tau之间。有 越来越多的证据表明凋亡样过程可能有助于 阿尔茨海默氏病以及其他神经退行性的神经元死亡 疾病。在阿尔茨海默氏病大脑中，高磷酸化的tau 形成配对的螺旋丝（PHF）。另外，微管结合的 phf-tau受到损害，但至少可以部分恢复 去磷酸化。因此，阿尔茨海默氏病期间的凋亡可能有助于 在这种疾病中积累的高磷酸化tau的形成， 从而进一步强调需要阐明控制tau的机制 在这些条件下的磷酸化。在AD大脑中，CDC2，酪蛋白Kinase1d（CK1D） 和CDK5升高，调查人员发现它们已增加 在凋亡期间。考虑到这些发现和其他发现 全面的工作假设是，在凋亡期间tau是 特定蛋白激酶在特定位点的过度磷酸化，这 高磷酸化导致TAU功能受损，这有助于 凋亡过程中发生的结构变化。阐明变化 在凋亡过程中发生的tau磷酸化中将有助于 了解导致Tau高磷酸化的过程 在AD和其他神经退行性疾病中。该提议的具体目的 正在测试以下假设：（1）在凋亡中，tau磷酸化。 特定站点以及CDC2，CK1D和CDK5活动的增加是 此过程的基本组成部分，（2）特定地点在tau上 在凋亡细胞中被磷酸化调节tau功能和定位， （3）在凋亡期间，tau具有正面颞痴呆， 帕金森氏症与17号染色​​体（FTDP-17）突变有关 与野生型tau相比，凤凰的局部和本地化。