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Updated: Apr 18, 2026

Assessment of Mitochondrial Fission/Fusion Dynamics in Kidney Proximal Tubular Cells
Published on: November 14, 2025
A role for the ancient SNARE syntaxin 17 in regulating mitochondrial division
Kohei Arasaki1, Hiroaki Shimizu1, Hirofumi Mogari1
1School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
Syntaxin 17 (Syn17) regulates mitochondrial fission by controlling Drp1 at ER-mitochondria contact sites. Nutrient levels impact this interaction, influencing mitochondrial dynamics during autophagy.
Area of Science:
- Cell Biology
- Molecular Biology
- Mitochondrial Dynamics
Background:
- Endoplasmic reticulum (ER) tubules are implicated in Drp1-mediated mitochondrial fission.
- The precise mechanism linking ER and mitochondrial fission remains largely unknown.
Purpose of the Study:
- To investigate the role of syntaxin 17 (Syn17) in ER-mitochondria contact sites and mitochondrial fission.
- To elucidate the mechanism by which Syn17 regulates mitochondrial dynamics.
Main Methods:
- Immunofluorescence microscopy to visualize Syn17 localization.
- Biochemical assays to study protein interactions (Syn17-Drp1).
- Analysis of ER calcium (Ca2+) homeostasis.
- Investigation of Syn17's role in nutrient-dependent mitochondrial regulation.
Main Results:
- Syn17 localizes to ER-mitochondria contact sites and promotes mitochondrial fission by regulating Drp1.
- The C-terminal hydrophobic domain of Syn17, not the SNARE domain, is crucial for this function.
- Syn17 influences ER Ca2+ levels and interacts with Rab32 in mitochondrial dynamics.
- Starvation disrupts the Syn17-Drp1 interaction, promoting mitochondrial elongation during autophagy.
Conclusions:
- Syn17 is a key regulator of ER-mitochondria contact sites, controlling mitochondrial fission.
- Syn17 acts as a nutrient-sensitive switch integrating ER, autophagosome, and mitochondrial functions.
- Syn17 is an ancient protein, suggesting its fundamental role in eukaryotic cell evolution.
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