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Updated: Jun 30, 2025

Author Spotlight: Unveiling Mitochondrial Contact Sites and Architectural Insights
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Author Spotlight: Unveiling Mitochondrial Contact Sites and Architectural Insights

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Mitochondria-ER contact sites expand during mitosis

Fang Yu1,2, Raphael Courjaret1,2, Lama Assaf1,3

  • 1Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.

Iscience
|March 21, 2024
PubMed

Insights

Mitochondria-ER contact sites (MERCS) expand during cell division (mitosis). This expansion enhances calcium (Ca2+) transfer between the ER and mitochondria, supporting cellular energy demands.

Area of Science:

  • Cell Biology
  • Mitochondrial Biology
  • Cellular Signaling

Background:

  • Mitochondria-ER contact sites (MERCS) are crucial for cellular functions like energy homeostasis and calcium signaling.
  • While MERCS are well-studied, their regulation and function during mitosis remain largely unknown.

Purpose of the Study:

  • To investigate the structural and functional changes of MERCS during mitosis.
  • To determine the impact of MERCS alterations on calcium transfer and cellular energetics during cell division.

Main Methods:

  • Utilized transmission electron microscopy (TEM) and serial EM with 3D reconstruction to visualize MERCS.
  • Employed a split GFP MERCS marker for live-cell imaging.
  • Measured direct calcium (Ca2+) levels and quantified Ca2+-dependent mitochondrial dehydrogenase activity.

Main Results:

  • Demonstrated significant expansion of MERCS across three cell types during mitosis.
  • Observed enhanced Ca2+ transfer between the endoplasmic reticulum (ER) and mitochondria in mitotic cells.
  • Showed increased activity of Ca2+-dependent mitochondrial enzymes, indicating heightened mitochondrial function.

Conclusions:

  • Mitotic MERCS undergo structural lengthening, leading to improved Ca2+ coupling between the ER and mitochondria.
  • This augmented Ca2+ signaling likely supports the elevated energy requirements of cells undergoing mitosis.
  • Findings provide new insights into the dynamic regulation of organelle contact sites during cell division.
Keywords:
Biological sciencesCell biologyNatural sciences

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