Zhong Ya-Ting, Huang Li-Li, Li Kangning, Yang Bingke, Ye Xueting, Zhong Hao-Ran, Yu Bing, Ma Menghan, Yuan Yuerong, Meng Yang, Pan Runfeng, Zhang Haiqing, Shi Lijun, Wang Yunyun, Tian Ruijun, Gao Song, Bian Xin
Guangdong Provincial Clinical Research Center for Cancer, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, China.
State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300071, China.
Proc Natl Acad Sci U S A. 2025 Apr 15;122(15):e2419449122. doi: 10.1073/pnas.2419449122. Epub 2025 Apr 8.
Most members of the dynamin superfamily of large guanosine triphophatases (GTPases) have an ability to remodel membranes in response to guanosine triphosphate (GTP) hydrolysis. Ring Finger Protein 112 (RNF112) (ZNF179/neurolastin) is a recently identified brain-specific dynamin-like protein possessing a really interesting new gene (RING) finger domain. Despite its essential role as an E3 ligase in neuron development, the architecture of RNF112 and the exact role of its GTPase activity remain unknown. Here, we determined the crystal structure of truncated RNF112 (RNF112) containing a GTPase domain (GD) and three-helical middle domain (MD) at different nucleotide-loading states. In the nucleotide-free (apo) state, the monomeric RNF112 remained in a unique self-restraint conformation characterized by docking of the proximal end of the MD to a groove in the GD. At the transition state of GTP hydrolysis, the MD was released from the GD and stretched aside to form an intertwined RNF112 homodimer. Engineered RNF112 equipped with the C-terminal elements of ATL1 or the two transmembrane domains of yeast Sac1p relocated to the endoplasmic reticulum and was capable of mediating membrane remodeling. Taken together, our results offer necessary understandings of RNF112 as a dynamin-like large GTPase in its cellular function and provide insights into the functional mechanisms of dynamin superfamily proteins.
大多数大型鸟苷三磷酸酶（GTP酶）的发动蛋白超家族成员具有响应鸟苷三磷酸（GTP）水解而重塑膜的能力。环指蛋白112（RNF112）（锌指蛋白179/神经弹性蛋白）是最近发现的一种大脑特异性发动蛋白样蛋白，具有一个非常有趣的新基因（RING）指结构域。尽管RNF112作为一种E3连接酶在神经元发育中起着至关重要的作用，但其结构以及GTP酶活性的确切作用仍不清楚。在这里，我们确定了截短的RNF112（RNF112）在不同核苷酸负载状态下包含GTP酶结构域（GD）和三螺旋中间结构域（MD）的晶体结构。在无核苷酸（脱辅基）状态下，单体RNF112保持独特的自我约束构象，其特征是MD的近端对接至GD中的一个凹槽。在GTP水解的过渡状态下，MD从GD释放并伸展到一侧，形成一个相互缠绕的RNF112同源二聚体。配备有ATL1 C末端元件或酵母Sac1p两个跨膜结构域的工程化RNF112重新定位于内质网，并能够介导膜重塑。综上所述，我们的结果为理解RNF112作为一种发动蛋白样大GTP酶的细胞功能提供了必要的认识，并为发动蛋白超家族蛋白的功能机制提供了见解。
