伊立替康(Irinotecan,CPT-11)是一种治疗癌症的化疗药物,主要代谢产物为7-乙基-10羟基喜树碱(7-Ethyl-10-hydroxycamptothecin,SN38).课题组实验筛选结果表明伊立替康对ataxin-3核质转运有潜在影响.通过免疫荧光、微孔过滤分析以及Preto...伊立替康(Irinotecan,CPT-11)是一种治疗癌症的化疗药物,主要代谢产物为7-乙基-10羟基喜树碱(7-Ethyl-10-hydroxycamptothecin,SN38).课题组实验筛选结果表明伊立替康对ataxin-3核质转运有潜在影响.通过免疫荧光、微孔过滤分析以及PretoBlue细胞活性检测等方法,探讨伊立替康对ataxin-3质核分离、突变ataxin-3形成的聚集体以及spinocerebellar ataxia type 3(SCA3)细胞活性的影响.结果表明伊立替康在10μM处理浓度时能够减少ataxin-3进入细胞核,但对蛋白聚集体没有影响;伊立替康在0.001μM或100μM处理浓度时,对SCA3细胞具有细胞毒性作用.本研究阐释了伊立替康对SCA3细胞模型的影响,揭示了旧药新靶点,为其他神经退行性疾病的致病机理和治疗药物研发提供新依据.展开更多
Objective Machado-Joseph disease （MJD）/Spinocerebellar ataxia type 3 （SCA3） is an autosomal dominant neurodegenerative disorder caused by an expansion of polyglutamine tract near the C-terminus of the MJD1 gene pr...Objective Machado-Joseph disease （MJD）/Spinocerebellar ataxia type 3 （SCA3） is an autosomal dominant neurodegenerative disorder caused by an expansion of polyglutamine tract near the C-terminus of the MJD1 gene product, ataxin-3. The precise mechanism of the MJD/SCA3 pathogenesis remains unclear. A growing body of evidence demonstrates that phosphorylation plays an important role in the pathogenesis of many neurodegenerative diseases. However, few kinases are known to phosphorylate ataxin-3. The present study is to explore whether ataxin-3 is a substrate of casein kinase 2 （CK2）. Methods The interaction between ataxin-3 and CK2 was identified by glutathione S-transferase （GST） pull-down assay and co-immunoprecipition assay. The phosphorylation of ataxin-3 by CK2 was measured by in vitro phosphorylation assays. Results （1） Both wild type and expanded ataxin-3 interacted with CK2α and CK2β in vitro. （2） In 293 cells, both wild type and expanded ataxin-3 interacted with CK2β, but not CK2α. （3） CK2 phosphorylated wild type and expanded ataxin-3. Conclusion Ataxin-3 is a substrate of protein kinase CK2.展开更多
<div style="text-align:justify;"> <span style="font-family:Verdana;">Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph Disease (MJD), is an autosomal dominant neurodege...<div style="text-align:justify;"> <span style="font-family:Verdana;">Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph Disease (MJD), is an autosomal dominant neurodegenerative disorder that predominantly involves the cerebellar, pyramidal, extrapyramidal, motor neuron and oculomotor systems. SCA3 presents strong phenotypic heterogeneity and its causative mutation of SCA3 consists of an expansion of a CAG tract in exon 10 of the <em>ATXN3</em> gene, situated at 14q32.1. The <em>ATXN3</em> gene is ubiquitously expressed in neuronal and non-neuronal tissues, and also participates in cellular protein quality control pathways. Mutated <em>ATXN3</em> alleles present about 45 to 87CAG repeats, which result in an expanded polyglutamine tract in ataxin-3. After mutation, the polyQ tract reaches the pathological threshold (about 50 glutamine residues);the protein is considered that it might gain a neurotoxic function through some unclear mechanisms. We reviewed the literature on the pathogenesis and therapeutic strategies of spinocerebellar ataxia type 3 patients. Conversion of the expanded protein is possible by enhancing protein refolding and degradation or preventing proteolytic cleavage and prevents the protein to reach the site of toxicity by altering its ability to translocate between the nucleus and cytoplasm. Proteasomal degradation and enhancing autophagic aggregate clearance are currently proposed remarkable therapy. In spite of extensive research, the molecular mechanisms of cellular toxicity resulting from mutant ataxin-3 remain no preventive treatment is currently available. These therapeutic strategies might be able to improve sign symptoms of SCA3 as well as slow the disease progression.</span> </div>展开更多
文摘伊立替康(Irinotecan,CPT-11)是一种治疗癌症的化疗药物,主要代谢产物为7-乙基-10羟基喜树碱(7-Ethyl-10-hydroxycamptothecin,SN38).课题组实验筛选结果表明伊立替康对ataxin-3核质转运有潜在影响.通过免疫荧光、微孔过滤分析以及PretoBlue细胞活性检测等方法,探讨伊立替康对ataxin-3质核分离、突变ataxin-3形成的聚集体以及spinocerebellar ataxia type 3(SCA3)细胞活性的影响.结果表明伊立替康在10μM处理浓度时能够减少ataxin-3进入细胞核,但对蛋白聚集体没有影响;伊立替康在0.001μM或100μM处理浓度时,对SCA3细胞具有细胞毒性作用.本研究阐释了伊立替康对SCA3细胞模型的影响,揭示了旧药新靶点,为其他神经退行性疾病的致病机理和治疗药物研发提供新依据.
基金the National Natural Sciences Foundation of China (No. 30770664)a grant from Educational Committee of Anhui Province, China (No. ZD2008008-2).
文摘Objective Machado-Joseph disease （MJD）/Spinocerebellar ataxia type 3 （SCA3） is an autosomal dominant neurodegenerative disorder caused by an expansion of polyglutamine tract near the C-terminus of the MJD1 gene product, ataxin-3. The precise mechanism of the MJD/SCA3 pathogenesis remains unclear. A growing body of evidence demonstrates that phosphorylation plays an important role in the pathogenesis of many neurodegenerative diseases. However, few kinases are known to phosphorylate ataxin-3. The present study is to explore whether ataxin-3 is a substrate of casein kinase 2 （CK2）. Methods The interaction between ataxin-3 and CK2 was identified by glutathione S-transferase （GST） pull-down assay and co-immunoprecipition assay. The phosphorylation of ataxin-3 by CK2 was measured by in vitro phosphorylation assays. Results （1） Both wild type and expanded ataxin-3 interacted with CK2α and CK2β in vitro. （2） In 293 cells, both wild type and expanded ataxin-3 interacted with CK2β, but not CK2α. （3） CK2 phosphorylated wild type and expanded ataxin-3. Conclusion Ataxin-3 is a substrate of protein kinase CK2.
文摘<div style="text-align:justify;"> <span style="font-family:Verdana;">Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph Disease (MJD), is an autosomal dominant neurodegenerative disorder that predominantly involves the cerebellar, pyramidal, extrapyramidal, motor neuron and oculomotor systems. SCA3 presents strong phenotypic heterogeneity and its causative mutation of SCA3 consists of an expansion of a CAG tract in exon 10 of the <em>ATXN3</em> gene, situated at 14q32.1. The <em>ATXN3</em> gene is ubiquitously expressed in neuronal and non-neuronal tissues, and also participates in cellular protein quality control pathways. Mutated <em>ATXN3</em> alleles present about 45 to 87CAG repeats, which result in an expanded polyglutamine tract in ataxin-3. After mutation, the polyQ tract reaches the pathological threshold (about 50 glutamine residues);the protein is considered that it might gain a neurotoxic function through some unclear mechanisms. We reviewed the literature on the pathogenesis and therapeutic strategies of spinocerebellar ataxia type 3 patients. Conversion of the expanded protein is possible by enhancing protein refolding and degradation or preventing proteolytic cleavage and prevents the protein to reach the site of toxicity by altering its ability to translocate between the nucleus and cytoplasm. Proteasomal degradation and enhancing autophagic aggregate clearance are currently proposed remarkable therapy. In spite of extensive research, the molecular mechanisms of cellular toxicity resulting from mutant ataxin-3 remain no preventive treatment is currently available. These therapeutic strategies might be able to improve sign symptoms of SCA3 as well as slow the disease progression.</span> </div>
