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Visualization and Quantification of Endogenous Intra-Organelle Protein Interactions at ER-Mitochondria Contact Sites by Proximity Ligation Assays
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Visualization and Quantification of Endogenous Intra-Organelle Protein Interactions at ER-Mitochondria Contact Sites by Proximity Ligation Assays

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ER-mitochondria associations are regulated by the VAPB-PTPIP51 interaction and are disrupted by ALS/FTD-associated

Radu Stoica1, Kurt J De Vos2, Sébastien Paillusson3

  • 11] Department of Neuroscience, Institute of Psychiatry, Kings College London, London SE5 8AF, UK [2] Clinical Neurosciences, Institute of Psychiatry, Kings College London, London SE5 8AF, UK [3].

Nature Communications
|June 4, 2014
PubMed

Insights

Researchers discovered that the protein TDP-43 disrupts connections between the endoplasmic reticulum (ER) and mitochondria. This disruption affects cellular calcium (Ca2+) balance and involves the VAPB-PTPIP51 interaction, revealing a new disease mechanism.

Area of Science:

  • Cell Biology
  • Neuroscience
  • Molecular Biology

Background:

  • Mitochondria and endoplasmic reticulum (ER) interactions are crucial for cellular functions.
  • Mechanisms regulating ER-mitochondria tethering are not fully understood.
  • Disrupted ER-mitochondria associations are implicated in neurodegenerative diseases.

Purpose of the Study:

  • To elucidate the molecular mechanisms underlying ER-mitochondria tethering.
  • To investigate the role of VAPB and PTPIP51 in ER-mitochondria associations.
  • To explore the impact of TDP-43 on ER-mitochondria interactions and cellular homeostasis.

Main Methods:

  • Investigated protein interactions using co-immunoprecipitation.
  • Assessed ER-mitochondria association dynamics.
  • Analyzed cellular calcium (Ca2+) homeostasis.
  • Examined the role of glycogen synthase kinase-3β (GSK-3β).

Main Results:

  • VAPB (ER-resident protein) interacts with PTPIP51 (mitochondrial protein) to regulate ER-mitochondria associations.
  • TDP-43 perturbs ER-mitochondria interactions, disrupting the VAPB-PTPIP51 interaction and Ca2+ homeostasis.
  • Overexpression of TDP-43 activates GSK-3β, which in turn regulates the VAPB-PTPIP51 interaction.

Conclusions:

  • Identified a novel mechanism by which TDP-43 disrupts ER-mitochondria associations.
  • The VAPB-PTPIP51 interaction is a key regulator of ER-mitochondria tethering.
  • This pathway provides new insights into the pathogenesis of neurodegenerative diseases linked to TDP-43.

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