Molecular and structural mechanisms of ZZ domain-mediated cargo selection by Nbr1
Molecular and structural mechanisms of ZZ domain-mediated cargo selection by Nbr1
复制标题
DOI：
10.15252/embj.2020107497
复制
发表时间：
2021-06-25
期刊：
影响因子：
11.4
通讯作者：
Du, Li-Lin
中科院分区：
文献类型：
--
作者：
Wang, Ying-Ying;Zhang, Jianxiu;Du, Li-Lin
在选择性自噬中，货物的选择性由自噬受体决定。然而，对于自噬受体是如何识别特定蛋白质的，人们仍然知之甚少。在裂解酵母中，一种被称为Nbr1介导的空泡靶向(NVT)的选择性自噬途径利用Nbr1，一种在包括人类在内的真核生物中保守的自噬受体，将胞浆水解酶靶向空泡。在这里，我们发现了两个新的NVT糖蛋白，甘露糖苷酶AMS1和氨基肽酶Ape4，它们竞争性地与Nbr1的第一个ZZ结构域(Nbr1-ZZ1)结合。高分辨率冷冻-EM分析揭示了单个ZZ结构域如何识别两个不同的蛋白质货物。Nbr1-ZZ1不仅通过保守的酸性口袋识别货物的N-末端，类似于其他特征的ZZ结构域，而且还以货物特有的方式与货物的其他部分结合。我们的发现揭示了自噬货物识别的单域双特异性机制，阐明了其潜在的结构基础，并扩大了对ZZ结构域介导的蛋白质-蛋白质相互作用的理解。
In selective autophagy, cargo selectivity is determined by autophagy receptors. However, it remains scarcely understood how autophagy receptors recognize specific protein cargos. In the fission yeast Schizosaccharomyces pombe, a selective autophagy pathway termed Nbr1-mediated vacuolar targeting (NVT) employs Nbr1, an autophagy receptor conserved across eukaryotes including humans, to target cytosolic hydrolases into the vacuole. Here, we identify two new NVT cargos, the mannosidase Ams1 and the aminopeptidase Ape4, that bind competitively to the first ZZ domain of Nbr1 (Nbr1-ZZ1). High-resolution cryo-EM analyses reveal how a single ZZ domain recognizes two distinct protein cargos. Nbr1-ZZ1 not only recognizes the N-termini of cargos via a conserved acidic pocket, similar to other characterized ZZ domains, but also engages additional parts of cargos in a cargo-specific manner. Our findings unveil a single-domain bispecific mechanism of autophagy cargo recognition, elucidate its underlying structural basis, and expand the understanding of ZZ domain-mediated protein-protein interactions.