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Updated: Dec 25, 2025

Quantitative Analysis of Mitochondria-Associated Endoplasmic Reticulum Membrane (MAM) Stabilization in a Neural Model of Alzheimer's Disease (AD)
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Endoplasmic reticulum-associated degradation regulates mitochondrial dynamics in brown adipocytes

Zhangsen Zhou1, Mauricio Torres1, Haibo Sha2

  • 1Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA.

Science (New York, N.Y.)
|March 21, 2020
PubMed

Insights

Mitochondria-associated membranes (MAMs) are crucial for ER-mitochondria communication. Loss of the Sel1L-Hrd1 ER-associated degradation (ERAD) complex in brown adipocytes causes mitochondrial dysfunction and cold sensitivity.

Area of Science:

  • Cell Biology
  • Mitochondrial Biology
  • Endoplasmic Reticulum Biology

Background:

  • Specialized endoplasmic reticulum (ER) domains, known as mitochondria-associated membranes (MAMs), mediate crucial crosstalk between the ER and mitochondria.
  • The Sel1L-Hrd1 protein complex is a key component of ER-associated protein degradation (ERAD), a cellular process for clearing misfolded proteins.

Purpose of the Study:

  • To investigate the role of the Sel1L-Hrd1 ERAD complex in the formation of megamitochondria and the structure of MAMs in brown adipocytes.
  • To elucidate the impact of ERAD deficiency on mitochondrial dynamics and ER-mitochondria contacts.

Main Methods:

  • Utilized three-dimensional high-resolution imaging to analyze mitochondrial morphology and MAMs.
  • Investigated the physiological consequences of ERAD deficiency in brown adipocytes using mouse models.

Main Results:

  • ERAD deficiency in brown adipocytes led to the formation of pleomorphic megamitochondria with altered MAMs.
  • Mice with ERAD-deficient brown adipocytes displayed cold sensitivity and mitochondrial dysfunction.
  • ERAD deficiency disrupted ER-mitochondria contacts and mitochondrial dynamics, partly by regulating sigma receptor 1 (SigmaR1) turnover at MAMs.

Conclusions:

  • The Sel1L-Hrd1 ERAD complex is essential for maintaining normal ER-mitochondria crosstalk and mitochondrial function in brown adipocytes.
  • Dysregulation of ERAD impacts mitochondrial dynamics and cellular adaptation to cold stress.
  • This study provides novel molecular insights into the physiological significance of ER-mitochondrial interactions regulated by ERAD.

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