Department of Chemistry, College of Natural Sciences, Soongsil University, Seoul 06978, Republic of Korea.
College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
Structure. 2022 Nov 3;30(11):1530-1537.e3. doi: 10.1016/j.str.2022.08.005. Epub 2022 Sep 9.
The heterodimer of human ubiquitin fusion degradation 1 (hUfd1) and human nuclear protein localization 4 (hNpl4) is a major cofactor of human p97 adenosine triphosphatase (ATPase). The p97-Ufd1-Npl4 complex translocates the ubiquitin-conjugated proteins from the endoplasmic reticulum membrane to the cytoplasm. Ubiquitinated proteins are then degraded by the proteasome. The structures of Npl4 and Ufd1-Npl4 (UN) complex in Saccharomyces cerevisiae have been recently reported; however, the structures of hNpl4 and the human UN complex remain unknown. Here, we report the crystal structures of the human UN complex at a resolution of 2.7 Å and hNpl4 at a resolution of 3.0 Å. We also present atomic details and characterization of the human UN complex. Crystallographic studies and site-directed mutagenesis of the hUfd1 residues involved in the interaction with hNpl4 revealed the atomic details of the two proteins.
人泛素融合降解 1（hUfd1）和人核蛋白定位 4（hNpl4）的异二聚体是人类 p97 三磷酸腺苷酶（ATPase）的主要辅助因子。p97-Ufd1-Npl4 复合物将泛素缀合蛋白从内质网膜转运到细胞质。然后，泛素化蛋白被蛋白酶体降解。最近报道了酿酒酵母中 Npl4 和 Ufd1-Npl4（UN）复合物的结构；然而，hNpl4 和人 UN 复合物的结构仍然未知。在这里，我们报道了人 UN 复合物在 2.7Å分辨率和 hNpl4 在 3.0Å分辨率下的晶体结构。我们还呈现了人 UN 复合物的原子细节和特征。与 hNpl4 相互作用的 hUfd1 残基的晶体学研究和定点突变揭示了这两种蛋白质的原子细节。
