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Myosin-19 and Miro Regulate Mitochondria-Endoplasmic Reticulum Contacts and Mitochondria Inner Membrane Architecture
Aya Attia1,2, Katarzyna Majstrowicz1, Samruddhi Shembekar1
1Institute of Integrative Cell Biology and Physiology, University of Münster, Schlossplatz 5, 48149 Munster, Germany.
Cells
|November 13, 2025
Summary
Myosin XIX (Myo19) deficiency alters mitochondrial structure and function. Myo19 and Miro, but not TRAK1, regulate ER-mitochondria contact sites, impacting cellular health.
Area of Science:
- Cell Biology
- Mitochondrial Biology
- Organelle Dynamics
Background:
- Mitochondrial dynamics are crucial for cellular health, involving complex processes like fusion, fission, and organelle contact formation.
- Myosin XIX (Myo19), an actin-based motor, interacts with mitochondrial receptors (Miro), but its role in mitochondrial dynamics remains unclear.
- Understanding Myo19's function is vital for elucidating mitochondrial regulation.
Purpose of the Study:
- To investigate the role of Myosin XIX (Myo19) in mitochondrial dynamics and cellular health.
- To characterize the ultrastructural and functional consequences of Myo19 deficiency in mitochondria.
- To compare the functions of Myo19 with microtubule-based motors (TRAK1/2) and their receptors (Miro).
Main Methods:
- Generation and analysis of Myosin XIX (Myo19)-deficient mouse models.
- Ultrastructural examination of mitochondria in Myo19-deficient MEFs and HEK cells.
- Analysis of Miro-deficient HEK cells and TRAK1-deficient HAP1 cells.
- Measurement of oxygen consumption rates and OXPHOS supercomplex abundance.
Main Results:
- Myo19 deficiency leads to morphological alterations in mitochondrial inner membranes, with fewer and malformed cristae.
- Mitochondria in Myo19-deficient cells exhibit reduced endoplasmic reticulum-mitochondria contact sites (ERMCSs).
- Loss of Myo19 or Miro results in decreased oxygen consumption and OXPHOS supercomplexes, while TRAK1 deficiency primarily affects cristae.
- Myo19 and Miro are specifically implicated in regulating ERMCSs.
Conclusions:
- Actin-based (Myo19) and microtubule-based (TRAK1) motors both influence mitochondrial cristae formation.
- Myosin XIX (Myo19), through its interaction with Miro, plays a critical role in maintaining ER-mitochondria contact sites.
- These findings highlight distinct roles for Myo19 and TRAK1 in mitochondrial morphology and organelle communication.
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