为了找到这一现象的原因以及铁死亡是否存在平行于GPX4的信号调控方式,2019年10月21日,德国Neuherberg发育遗传学研究所Marcus Conrad研究组与德国Würzburg Rudolf Virchow实验生物医学中心José Pedro Friedmann Angeli研究组合作,加州大学伯克利分校的James A. Olzmann研究组(以下简称德国组与美国组)在Nature以背靠背方式发表文章,分别题为FSP1 is a glutathione-independent ferroptosis suppressor与The CoQ oxidoreductase FSP1 acts parallel to GPX4 to inhibit ferroptosis,鉴定出了独立于GPX4的新颖的铁死亡信号通路。
为了解决该问题,德国组的实验方案是通过在GPX4缺失的情况下下进行筛选,找到能够补足GPX4引起铁死亡的其他因子(图1)。而美国组采用了合成致死CRISPR-Cas9的筛选方案(图2)。两个研究组同时发现了铁死亡抑制蛋白FSP1(Ferroptosis suppressor protein 1),FSP1最初被鉴定时称为AIFM2(Apoptosis-inducing factor mitochondrial 2)。AIFM2是由于与凋亡相关的因子AIFM1存在序列相似性而被命名【9】,为了防止混淆,德、美两个研究组决定将该蛋白的名字改为FSP1。FSP1在细胞中过表达能够显著保护细胞免受铁死亡诱导因子引发铁死亡的影响。这是迄今为止,首次发现能够补偿GPX4缺失的酶催化系统。
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