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

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.

• Authors: Lin Chen, Na Li, Meiqi Zhang, Mingming Sun, Jiaxuan Bian, Bo Yang, Zhengcunxiao Li, Jiayu Wang, Fei Li, Xiaomeng Shi, Yuan Wang, Feng Yuan, Peng Zou, Changliang Shan, Jing Wang
• Journal: Angewandte Chemie (International ed. in English) (Angew Chem Int Ed Engl) Vol. 60 Issue 48 Pg. 25346-25355 (11 22 2021) ISSN: 1521-3773 [Electronic] Germany
• PMID: 34550632 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2021 Wiley-VCH GmbH.

Chemical References

• ATOX1 protein, human
• Adaptor Proteins, Signal Transducing
• CRIP2 protein, human
• Copper Transport Proteins
• LIM Domain Proteins
• Molecular Chaperones
• Multifunctional Enzymes
• Copper
• Endonucleases
• APEX2 protein, human
• DNA-(Apurinic or Apyrimidinic Site) Lyase

Topics

• Adaptor Proteins, Signal Transducing (metabolism)
• Autophagy
• Cell Line, Tumor
• Copper (metabolism)
• Copper Transport Proteins (metabolism)
• DNA-(Apurinic or Apyrimidinic Site) Lyase (metabolism)
• Endonucleases (metabolism)
• Humans
• LIM Domain Proteins (metabolism)
• Molecular Chaperones (metabolism)
• Multifunctional Enzymes (metabolism)