Autosomal recessive spinocerebellar ataxias(SCARs)are one of the most common neurodegenerative diseases characterized by progressive ataxia.Although SCARs are known to be caused by mutations in multiple genes,there ar...Autosomal recessive spinocerebellar ataxias(SCARs)are one of the most common neurodegenerative diseases characterized by progressive ataxia.Although SCARs are known to be caused by mutations in multiple genes,there are still many cases that go undiagnosed or are misdiagnosed.In this study,we presented a SCAR patient,and identified a probable novel pathogenic mutation(c.1A>G,p.M1V)in the AFG3L2 start codon.The proband's genotype included heterozygous mutations of the compound AFG3L2(p.[M1V];[R632X](c.[1A>G];[1894.C>T])),which were inherited from the father(c.1A>G,p.M1V)and mother(c.1894C>T,p.R632X).Functional studies performed on hi PSCs(human induced pluripotent stem cells)generated from the patients and HEK293T cells showed that the mutations impair mitochondrial function and the unbalanced expression of AFG3L2 mRNA and protein levels.Furthermore,this novel mutation resulted in the degradation of the protein and the reduction of the stability of the AFG3L2 protein,and MCU(mitochondrial calcium uniporter)complex mediated Ca2+overload.展开更多
线粒体是真核细胞中最重要的能量产生细胞器,在物质代谢、细胞信号转导、氧化应激,以及多种形式的细胞死亡途径中发挥关键的调控作用。线粒体拥有独立于细胞核基因组的DNA——线粒体DNA(mtDNA),但是只编码13条多肽链、22个转运RNA(tRNA)...线粒体是真核细胞中最重要的能量产生细胞器,在物质代谢、细胞信号转导、氧化应激,以及多种形式的细胞死亡途径中发挥关键的调控作用。线粒体拥有独立于细胞核基因组的DNA——线粒体DNA(mtDNA),但是只编码13条多肽链、22个转运RNA(tRNA)和2个核糖体RNA(r RNA)。线粒体内的其他蛋白质都是由核基因(n DNA)编码的,这两个基因组协同工作,维持细胞的正常功能和稳态。已鉴定的人类细胞线粒体蛋白质组含有超过1158种蛋白质,它们分别定位于线粒体外膜、膜间隙、内膜和基质中,参与氧化磷酸化、三羧酸循环、分裂-融合动力学,以及维持线粒体稳态等重要功能。线粒体稳态和线粒体功能的正常发挥与线粒体蛋白酶密切相关,这些线粒体蛋白酶通过调节线粒体蛋白的活性,去除受损的或不必要的蛋白质,从而维持线粒体稳态并确保细胞存活。其中一组功能依赖于ATP结合和水解的线粒体AAA+蛋白酶(ATPases associated with diverse cellular activities,AAA+proteases),不仅执行降解错误折叠蛋白质的功能,还在线粒体融合蛋白的加工成熟、呼吸链复合物组装、mtDNA复制/转录等过程中发挥关键作用。研究发现,这些线粒体AAA+蛋白酶的基因突变或者表达异常导致其酶活性改变,严重损害线粒体结构和功能的完整性,并导致多种神经系统疾病的发生。本文主要以Lon蛋白酶1(Lon peptidase 1,LONP1)、酵母线粒体逃逸基因1样蛋白1(yeast mitochondrial escape 1 like 1,YME1L1)和ATP酶家族基因3样蛋白2(ATPase family gene 3-like 2,AFG3L2)等3种线粒体AAA+蛋白酶为例,详细阐述了它们的序列相似性和结构特点,以及在线粒体中的不同定位与功能。通过总结这3种蛋白酶基因突变与神经系统疾病的关系,发现已报道的疾病相关突变主要位于ATPase结构域和水解酶或肽酶结构域。因此,解析这些蛋白酶关键结构域的结构和突变导致的功能变化及其对线粒体乃至细胞稳态的影响,将为理解疾病机制和研发靶向干预策略提供参考。展开更多
基金supported by the National Key Research and Development Program of China(2019YFA0801402)the National Natural Science Foundation of China(82271890)+3 种基金the Shanghai Key Clinical Specialty Project(shslczdzk05705)the Shanghai Top Priority Key Discipline Project(2017ZZ02019)Innovative Research Team of High-Level Local Universities in Shanghai(SHSMU-ZDCX20212200)the Macao Science and Technology Development Fund(FDCT)(0092/2022/A2,003/2022/ALC)。
文摘Autosomal recessive spinocerebellar ataxias(SCARs)are one of the most common neurodegenerative diseases characterized by progressive ataxia.Although SCARs are known to be caused by mutations in multiple genes,there are still many cases that go undiagnosed or are misdiagnosed.In this study,we presented a SCAR patient,and identified a probable novel pathogenic mutation(c.1A>G,p.M1V)in the AFG3L2 start codon.The proband's genotype included heterozygous mutations of the compound AFG3L2(p.[M1V];[R632X](c.[1A>G];[1894.C>T])),which were inherited from the father(c.1A>G,p.M1V)and mother(c.1894C>T,p.R632X).Functional studies performed on hi PSCs(human induced pluripotent stem cells)generated from the patients and HEK293T cells showed that the mutations impair mitochondrial function and the unbalanced expression of AFG3L2 mRNA and protein levels.Furthermore,this novel mutation resulted in the degradation of the protein and the reduction of the stability of the AFG3L2 protein,and MCU(mitochondrial calcium uniporter)complex mediated Ca2+overload.
文摘线粒体是真核细胞中最重要的能量产生细胞器,在物质代谢、细胞信号转导、氧化应激,以及多种形式的细胞死亡途径中发挥关键的调控作用。线粒体拥有独立于细胞核基因组的DNA——线粒体DNA(mtDNA),但是只编码13条多肽链、22个转运RNA(tRNA)和2个核糖体RNA(r RNA)。线粒体内的其他蛋白质都是由核基因(n DNA)编码的,这两个基因组协同工作,维持细胞的正常功能和稳态。已鉴定的人类细胞线粒体蛋白质组含有超过1158种蛋白质,它们分别定位于线粒体外膜、膜间隙、内膜和基质中,参与氧化磷酸化、三羧酸循环、分裂-融合动力学,以及维持线粒体稳态等重要功能。线粒体稳态和线粒体功能的正常发挥与线粒体蛋白酶密切相关,这些线粒体蛋白酶通过调节线粒体蛋白的活性,去除受损的或不必要的蛋白质,从而维持线粒体稳态并确保细胞存活。其中一组功能依赖于ATP结合和水解的线粒体AAA+蛋白酶(ATPases associated with diverse cellular activities,AAA+proteases),不仅执行降解错误折叠蛋白质的功能,还在线粒体融合蛋白的加工成熟、呼吸链复合物组装、mtDNA复制/转录等过程中发挥关键作用。研究发现,这些线粒体AAA+蛋白酶的基因突变或者表达异常导致其酶活性改变,严重损害线粒体结构和功能的完整性,并导致多种神经系统疾病的发生。本文主要以Lon蛋白酶1(Lon peptidase 1,LONP1)、酵母线粒体逃逸基因1样蛋白1(yeast mitochondrial escape 1 like 1,YME1L1)和ATP酶家族基因3样蛋白2(ATPase family gene 3-like 2,AFG3L2)等3种线粒体AAA+蛋白酶为例,详细阐述了它们的序列相似性和结构特点,以及在线粒体中的不同定位与功能。通过总结这3种蛋白酶基因突变与神经系统疾病的关系,发现已报道的疾病相关突变主要位于ATPase结构域和水解酶或肽酶结构域。因此,解析这些蛋白酶关键结构域的结构和突变导致的功能变化及其对线粒体乃至细胞稳态的影响,将为理解疾病机制和研发靶向干预策略提供参考。
