Mechanistic insights into the iron-sulfur cluster- dependent interaction of the autophagy receptor NCOA4 with the E3 ligase HERC2

• 成果类型: Article
• 署名作者: Liu, Haobo; Shen, Liqiang; Gong, Xinyu; Zhou, Xindi; Huang, Yichao; Zhou, Yuqian; Guo, Zhenpeng; Guo, Hanbo; Wang, Shichao; Pan, Lifeng
• 署名单位: Chinese Academy of Sciences; Shanghai Institute of Organic Chemistry, CAS; University of Chinese Academy of Sciences, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9407
• DOI: 10.1073/pnas.2510269122
• 发表日期: 2025-07-29
• 关键词: selective autophagy; molecular-basis; degradation; proteins; RECOGNITION; homeostasis; optineurin; restricts; adapter

摘要

NCOA4, a dedicated autophagy receptor for mediating selective autophagy of ferritin (ferritinophagy), plays a vital role in maintaining cellular iron homeostasis. The cellular abundance of NCOA4 is regulated by the E3 ligase HERC2 that can specifically tar- get NCOA4 for proteasomal degradation under iron-- replete conditions. However, the detailed molecular mechanism governing the iron-- dependent recognition of NCOA4 by HERC2 remains elusive. Here, using multidisciplinary approaches, we systematically characterize the HERC2-- binding domain (HBD) of NCOA4 , its interaction with HERC2. We uncover that NCOA4 HBD harbors a [2Fe- 2S]- 2S] cluster and can exist in two different states, the apo- form state and the [2Fe- 2S]- 2S] cluster-bound state. Moreover, we unravel that HERC2 can effectively recognize the [2Fe- 2S]- 2S] cluster-bound NCOA4 HBD through its Cullin-- 7- PARC- HERC2- PARC- HERC2 (CPH) domain and iron-sulfur cluster-dependent NCOA4-- binding domain (INBD) with a synergistic binding mode. The determined crys- tal structures of HERC2(2540- 2700)- 2700) and its complex with the [2Fe- 2S]- 2S] cluster-bound NCOA4 HBD together with relevant biochemical and cellular results not only elucidate how NCOA4 HBD specifically senses cellular iron level by binding a [2Fe- 2S]- 2S] cluster but also reveal the molecular basis underlying the specific interaction of HERC2 with the [2Fe- 2S]- 2S] cluster-bound NCOA4 HBD. In summary, our findings provide mechanistic insights into the iron-- dependent turnover of NCOA4 by HERC2 and expand our under- standing of the regulatory mechanism of NCOA4-- mediated ferritinophagy.