Degradation of AMPK by a cancer-specific ubiquitin ligase

Carlos T. Pineda, Saumya Ramanathan, Klementina Fon Tacer, Jenny L. Weon, Malia B. Potts, Yi Hung Ou, Michael A. White, Patrick Ryan Potts

Research output: Contribution to journalArticlepeer-review

162 Scopus citations

Abstract

AMP-activated protein kinase (AMPK) is a master sensor and regulator of cellular energy status. Upon metabolic stress, AMPK suppresses anabolic and promotes catabolic processes to regain energy homeostasis. Cancer cells can occasionally suppress the growth-restrictive AMPK pathway by mutation of an upstream regulatory kinase. Here, we describe a widespread mechanism to suppress AMPK through its ubiquitination and degradation by the cancer-specific MAGE-A3/6-TRIM28 ubiquitin ligase. MAGE-A3 and MAGE-A6 are highly similar proteins normally expressed only in the male germline but frequently re-activated in human cancers. MAGE-A3/6 are necessary for cancer cell viability and are sufficient to drive tumorigenic properties of non-cancerous cells. Screening for targets of MAGE-A3/6-TRIM28 revealed that it ubiquitinates and degrades AMPKα1. This leads to inhibition of autophagy, activation of mTOR signaling, and hypersensitization to AMPK agonists, such as metformin. These findings elucidate a germline mechanism commonly hijacked in cancer to suppress AMPK.

Original languageEnglish (US)
Pages (from-to)715-728
Number of pages14
JournalCell
Volume160
Issue number4
DOIs
StatePublished - Feb 12 2015

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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