Inositol serves as a natural inhibitor of mitochondrial fission by directly targeting AMPK.

Abstract

Mitochondrial dynamics regulated by mitochondrial fusion and fission maintain mitochondrial functions, whose alterations underline various human diseases. Here, we show that inositol is a critical metabolite directly restricting AMPK-dependent mitochondrial fission independently of its classical mode as a precursor for phosphoinositide generation. Inositol decline by IMPA1/2 deficiency elicits AMPK activation and mitochondrial fission without affecting ATP level, whereas inositol accumulation prevents AMPK-dependent mitochondrial fission. Metabolic stress or mitochondrial damage causes inositol decline in cells and mice to elicit AMPK-dependent mitochondrial fission. Inositol directly binds to AMPKγ and competes with AMP for AMPKγ binding, leading to restriction of AMPK activation and mitochondrial fission. Our study suggests that the AMP/inositol ratio is a critical determinant for AMPK activation and establishes a model in which AMPK activation requires inositol decline to release AMPKγ for AMP binding. Hence, AMPK is an inositol sensor, whose inactivation by inositol serves as a mechanism to restrict mitochondrial fission.

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Citation

Published Version (Please cite this version)

10.1016/j.molcel.2021.08.025

Publication Info

Hsu, Che-Chia, Xian Zhang, Guihua Wang, Weina Zhang, Zhen Cai, Bo-Syong Pan, Haiwei Gu, Chuan Xu, et al. (2021). Inositol serves as a natural inhibitor of mitochondrial fission by directly targeting AMPK. Molecular cell, 81(18). pp. 3803–3819.e7. 10.1016/j.molcel.2021.08.025 Retrieved from https://hdl.handle.net/10161/31157.

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Scholars@Duke

Hsu

Che-Chia Hsu

Assistant Professor of Pathology

My research has focused on mitochondrial functions in cancer metabolism and understand the role of mitochondrial dynamics in cellular function and human diseases including cancers. Additionally, I also continuously dissect cancer metabolism and identifying potential metabolic vulnerabilities of cancer initiation, progression and metastasis using several in vitroex vivo and in vivo genetical approaches such as CRISPR/Cas9 knockout, mouse/ human organoid cultures and genetically engineered mouse models, thereby characterizing molecular mechanisms regulated by metabolic pathways and developing potential metabolic interventions for targeting cancers. 

RAJESHKUMAR MANNE

Research Associate, Senior
Lin

Hui-Kuan Lin

Fred and Janet Sanfilippo Distinguished Professor

The research interest in Dr. Lin lab is to understand oncogenic networks between oncogenes and tumor suppressor genes, dissect the regulatory mechanisms underlying  the crosstalk between ageing and cancer, to unravel the role of posttranslational modifications (PTMs) such as ubiquitination  and metabolism in diverse molecular and biological processes important for cancer progression and metastasis, cancer stem regulation, cancer immunity and drug resistance by using biochemical and molecular approaches along with and genetic mouse models, and finally to develop small molecule inhibitors and antibodies targeting critical oncogenic signaling and metabolic vulnerabilities for cancer treatment. His research goals aim to not only reveal fundamental insights and concepts for cancer biology and cancer immunity, but also develop novel paradigms and therapeutic strategies for targeting human cancer and overcoming drug resistance.

Research interests include:

  • Crosstalk between oncogenic and tumor suppressor networks
  • Posttranslational modifications in signaling and cancer
  • Cancer progression and metastasis
  • Biology of normal and cancer stem cells
  • Metabolism in cancer and ageing

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