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Study of Protein-protein Interactions in Autophagy Research
14:08

Study of Protein-protein Interactions in Autophagy Research

Published on: September 9, 2017

A non-canonical MEK/ERK signaling pathway regulates autophagy via regulating Beclin 1

Jianrong Wang1, Mary W Whiteman, Huiqin Lian

  • 1Medical College, Shantou University, Guangdong 515041, China. jrwang@stu.edu.cn

The Journal of Biological Chemistry
|June 13, 2009
PubMed

Insights

The AMP-activated protein kinase (AMPK) pathway regulates autophagy via the MEK/ERK module, controlling Beclin 1 levels. Differential activation thresholds of this pathway determine whether autophagy is protective or destructive.

Area of Science:

  • Cellular Biology
  • Molecular Signaling
  • Autophagy Research

Background:

  • Autophagy-essential proteins mediate protective or destructive cellular processes.
  • Signaling mechanisms governing these proteins and autophagy's opposing roles remain poorly understood.
  • Mammalian autophagy regulation involves complex protein interactions and signaling cascades.

Purpose of the Study:

  • To elucidate the signaling mechanisms controlling autophagy-essential proteins.
  • To investigate the role of the MEK/ERK module in autophagy regulation.
  • To understand how this pathway influences Beclin 1 and determines autophagy's outcome.

Main Methods:

  • Investigated the non-canonical MEK/ERK module downstream of AMPK and upstream of TSC.
  • Examined the regulation of Beclin 1 by MEK/ERK signaling.
  • Analyzed the impact of MEK/ERK on mammalian target of rapamycin complex 1 (mTORC1) and mTORC2.
  • Assessed the consequences of varying MEK/ERK activation levels on autophagy.

Main Results:

  • Depletion of ERK partially inhibited autophagy; MEK inhibition completely blocked it, indicating MEK's critical role.
  • Basal MEK/ERK activity maintains basal Beclin 1 by preventing mTORC1 and mTORC2 disassembly.
  • AMPK-activated MEK/ERK disassembles mTORC1 via TSC and mTORC2 independently of TSC.
  • Moderate MEK/ERK activation leads to cytoprotective autophagy; sustained activation causes cytodestructive autophagy.

Conclusions:

  • The AMPK-MEK/ERK-TSC-mTOR pathway regulates Beclin 1 levels.
  • Different activation thresholds of this pathway dictate protective versus destructive autophagy.
  • This pathway provides a novel framework for understanding autophagy's dual roles.

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