Calcium-responsive transactivator (CREST) toxicity is rescued by loss of PBP1/ATXN2 function in a novel yeast proteinopathy model and in transgenic flies
Calcium-responsive transactivator (CREST) toxicity is rescued by loss of PBP1/ATXN2 function in a novel yeast proteinopathy model and in transgenic flies
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DOI：
10.1371/journal.pgen.1008308
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发表时间：
2019-08-01
期刊：
影响因子：
4.5
通讯作者：
Liebman, Susan W.
中科院分区：
文献类型：
--
作者：
Park, Sangeun;Park, Sei-Kyoung;Liebman, Susan W.
钙响应反式激活因子（CREST）蛋白的突变已被证明可导致肌萎缩侧索硬化症（ALS）。在这里，我们表明，在酵母中表达的人CREST蛋白的形式主要是核聚集体和有毒。我们还表明，酵母朊病毒繁殖所需的HSP 104分子伴侣同样需要CREST毒性。此外，HSP 104的缺失影响CREST聚集。ATXN 2此前已被证明可以改变由TDP-43编码基因突变引起的ALS毒性，也可以改变酵母或苍蝇中表达的CREST的毒性。此外，酵母ATXN 2直系同源物的缺失减少了CREST聚集。这些结果扩展了ALS相关蛋白的谱，其毒性由ATXN 2调节，表明靶向ATXN 2的治疗可能对广泛的神经退行性疾病有效。几种这样的蛋白质，例如TDP-43，在酵母中表达时聚集并且是有毒的。ATXN 2直系同源物PBP 1的缺失降低了酵母TDP-43的毒性，这导致ATXN 2被鉴定为肌萎缩性侧索硬化症（ALS）的危险因素和治疗靶点。同样，新的酵母神经退行性疾病模型可以促进识别其他风险因素和目标。SS 18 L1基因突变编码钙响应性反式激活因子（CREST）染色质重塑蛋白，与ALS相关。我们发现，CREST是有毒的酵母和形式的细胞核和偶尔的细胞质病灶，染色与硫磺素-T，一种染料指示淀粉样蛋白。像酵母染色质重塑因子SWI 1一样，CREST抑制FLO基因的沉默。CREST的毒性通过[PIN+]朊病毒增强，并通过删除许多酵母朊病毒繁殖所需的HSP 104伴侣蛋白而降低。同样，PBP 1的缺失降低了CREST毒性和聚集。在与酵母数据雅阁中，我们表明果蝇的人类ATXN 2的直系同源物dAtx 2是CREST毒性的有效增强剂。在视网膜神经节细胞中过表达CREST的果蝇中下调dAtx 2足以在很大程度上挽救由人CREST诱导的严重退行性表型。过表达引起相当大的共定位CREST和PBP 1/ATXN 2在酵母和哺乳动物细胞的细胞质病灶。因此，CREST和PBP 1/ATXN 2的共聚集可能是PBP 1/ATXN 2介导毒性的机制之一。这些结果扩展了ALS相关蛋白的谱，其毒性由PBP 1/ATXN 2调节，表明靶向ATXN 2的疗法可能对广泛的神经退行性疾病有效。
Author summary Mutations in the calcium-responsive transactivator (CREST) protein have been shown to cause amyotrophic lateral sclerosis (ALS). Here we show that the human CREST protein expressed in yeast forms largely nuclear aggregates and is toxic. We also show that the HSP104 chaperone required for propagation of yeast prions is likewise required for CREST toxicity. Furthermore deletion of HSP104 affects CREST aggregation. ATXN2, previously shown to modify ALS toxicity caused by mutations in the TDP-43 encoding gene, also modifies toxicity of CREST expressed in either yeast or flies. In addition, deletion of the yeast ATXN2 ortholog reduces CREST aggregation. These results extend the spectrum of ALS associated proteins whose toxicity is regulated by ATXN2, suggesting that therapies targeting ATXN2 may be effective for a wide range of neurodegenerative diseases.Proteins associated with familial neurodegenerative disease often aggregate in patients' neurons. Several such proteins, e.g. TDP-43, aggregate and are toxic when expressed in yeast. Deletion of the ATXN2 ortholog, PBP1, reduces yeast TDP-43 toxicity, which led to identification of ATXN2 as an amyotrophic lateral sclerosis (ALS) risk factor and therapeutic target. Likewise, new yeast neurodegenerative disease models could facilitate identification of other risk factors and targets. Mutations in SS18L1, encoding the calcium-responsive transactivator (CREST) chromatin-remodeling protein, are associated with ALS. We show that CREST is toxic in yeast and forms nuclear and occasionally cytoplasmic foci that stain with Thioflavin-T, a dye indicative of amyloid-like protein. Like the yeast chromatin-remodeling factor SWI1, CREST inhibits silencing of FLO genes. Toxicity of CREST is enhanced by the [PIN+] prion and reduced by deletion of the HSP104 chaperone required for the propagation of many yeast prions. Likewise, deletion of PBP1 reduced CREST toxicity and aggregation. In accord with the yeast data, we show that the Drosophila ortholog of human ATXN2, dAtx2, is a potent enhancer of CREST toxicity. Downregulation of dAtx2 in flies overexpressing CREST in retinal ganglion cells was sufficient to largely rescue the severe degenerative phenotype induced by human CREST. Overexpression caused considerable co-localization of CREST and PBP1/ATXN2 in cytoplasmic foci in both yeast and mammalian cells. Thus, co-aggregation of CREST and PBP1/ATXN2 may serve as one of the mechanisms of PBP1/ATXN2-mediated toxicity. These results extend the spectrum of ALS associated proteins whose toxicity is regulated by PBP1/ATXN2, suggesting that therapies targeting ATXN2 may be effective for a wide range of neurodegenerative diseases.