北京大学王晶团队报道了基于APEX2的Atox1邻近标记将CRIP2识别为调控自噬激活的核铜结合蛋白。相关研究成果发表在2021年9月22日出版的《德国应用化学》。

哺乳动物细胞核含有铜，已知癌细胞积累异常高的铜水平，但核积累的机制和铜更广泛的功能意义仍知之甚少。

该文中，研究人员通过结合基于APEX2的邻近标记和质谱，重点关注铜伴侣Atox1，确定了一种以前未被识别的核铜结合蛋白，富含半胱氨酸蛋白2（CRIP2），该蛋白在细胞核中与Atox1相互作用。研究人员发现Atox1将铜转移到CRIP2，从而导致CRIP2二级结构的改变，最终促进其泛素介导的蛋白酶体降解。最后，研究人员证明了CRIP2的缺失以及铜诱导的CRIP2降解提高了ROS水平并激活了H1299细胞中的自噬。

该研究证实CRIP2是一种自噬抑制蛋白，并表明在癌细胞中激活自噬过程中产生CRIP2介导的铜代谢。

研究人员表示，哺乳动物细胞核中含有铜，癌细胞也会积累异常高的铜水平，但核积累的机制和铜的更广泛的功能意义尚不清楚。

附：英文原文

Title: APEX2-based Proximity Labeling of Atox1 Identifies CRIP2 as a Nuclear Copper-binding Protein that Regulates Autophagy Activation

Author: Jing Wang, Lin Chen, Na Li, Meiqi Zhang, Mingming Sun, Jiaxuan Bian, Zhengcunxiao Li, Jiayu Wang, Fei Li, Xiaomeng Shi, Feng Yuan, Peng Zou, Changliang Shan, Bo Yang, Yuan Wang

Issue&Volume: 2021-09-22

Abstract: Mammalian cell nuclei contain copper, and cancer cells are known to accumulate aberrantly high copper levels, yet the mechanisms underlying nuclear accumulation and copper’s broader functional significance remain poorly understood. Here, by combining APEX2-based proximity labeling focused on the copper chaperone Atox1 with mass spectrometry we identified a previously unrecognized nuclear copper binding protein, Cysteine-rich protein 2 (CRIP2), that interacts with Atox1 in the nucleus. We show that Atox1 transfers copper to CRIP2, which induces a change in CRIP2’s secondary structure that ultimately promotes its ubiquitin-mediated proteasomal degradation. Finally, we demonstrate that depletion of CRIP2—as well as copper-induced CRIP2 degradation—elevates ROS levels and activates autophagy in H1299 cells. Thus, our study establishes that CRIP2 as an autophagic suppressor protein and implicates CRIP2-mediated copper metabolism in the activation of autophagy in cancer cells.

DOI: 10.1002/anie.202108961

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202108961