Related Experiment Video

Updated: Aug 19, 2025

In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice
08:40

In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice

Published on: November 22, 2017

17.7K

The roles of a mitochondrial protein Miga in autophagy

Lingna Xu1,2, Liquan Wang1, Chao Tong1,2

  • 1Department of Obstetrics, Life Sciences Institute, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.

Autophagy
|November 30, 2022
PubMed

Insights

Miga protein links mitochondria and autophagy by regulating key proteins and membrane contact sites. This connection is crucial for maintaining cellular homeostasis and proper autophagosome-lysosome fusion.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Autophagy Research

Background:

  • Miga is an evolutionarily conserved protein located on the outer mitochondrial membrane.
  • Miga facilitates endoplasmic reticulum (ER)-mitochondrial contacts via VAP protein interactions.
  • Miga is essential for autophagosome-lysosome fusion in macroautophagy/autophagy.

Purpose of the Study:

  • To elucidate the role of Miga in autophagy and cellular homeostasis.
  • To investigate Miga's interactions with components of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex.
  • To understand how Miga regulates ER-mitochondrial contact sites (ERMCS) and their impact on autophagy.

Main Methods:

  • Investigated Miga's binding partners, including Atg14 and Uvrag.
  • Analyzed the regulation of phosphatidylinositol-3-phosphate (PtdIns3P) levels by Miga.
  • Examined the effect of Miga on the stability of the SNARE protein Syx17 and ERMCS tethering.

Main Results:

  • Miga binds to Atg14 and Uvrag, alternative subunits of the PtdIns3K complex.
  • Miga regulates PtdIns3P levels through Uvrag interaction and ERMCS tethering.
  • Miga stabilizes Atg14, which is necessary for maintaining Syx17 levels.

Conclusions:

  • Miga establishes a direct link between mitochondria and autophagy.
  • Miga plays a critical role in autophagosome-lysosome fusion and cellular homeostasis.
  • Miga's function at ER-mitochondrial contact sites is key to its role in autophagy.
Keywords:
Autophagydrosophilaendoplasmic reticulum-mitochondrial contactsmitochondrionphosphatidylinositol-3 kinase

More Related Videos

Study of Protein-protein Interactions in Autophagy Research14:08

Study of Protein-protein Interactions in Autophagy Research

Published on: September 9, 2017

9.2K
Visualizing Mitophagy with Fluorescent Dyes for Mitochondria and Lysosome07:56

Visualizing Mitophagy with Fluorescent Dyes for Mitochondria and Lysosome

Published on: November 30, 2022

4.7K

Related Concept Videos

Autophagy01:27

Autophagy

Autophagy is a self-digesting process by which a cell protects itself from threats both within and outside the cell, ranging from abnormal proteins to invading bacteria. In this process, obsolete components of the cell and invading microbes are degraded by hydrolytic enzymes active in an acidic environment of the lysosomal lumen.
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
4.5K
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
3.2K
Mitochondrial Protein Sorting01:39

Mitochondrial Protein Sorting

Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death.  Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
4.4K
Delivery Pathways to the Lysosome01:36

Delivery Pathways to the Lysosome

Eukaryotic cells use different mechanisms to eliminate toxic waste obsolete and worn-out substances. Lysosomes play a pivotal role in this, and hence, these substances are carried to the lysosome from other parts of the cell and extracellular space through different pathways. The most elaborately studied pathways to the lysosome are the endocytic pathways.
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
6.7K
Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial...
2.6K
Autophagic Cell Death01:18

Autophagic Cell Death

Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
3.5K