Related Experiment Video
Updated: Jan 11, 2026
09:53
Author Spotlight: Advancing Techniques and Discoveries in Protein Synthesis and Assembly Through Innovative Mitochondrial Research
Published on: June 7, 2024
1.6K
Monitoring the complexity and dynamics of mitochondrial translation
Taisei Wakigawa1, Mari Mito2, Yushin Ando3
1RNA Systems Biochemistry Laboratory, Pioneering Research Institute, RIKEN, Wako, Saitama 351-0198, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
Molecular Cell
|November 13, 2025
Summary
Researchers developed new methods to study mitochondrial translation, revealing how it is regulated and influenced by tRNA modifications. This work offers a platform for understanding protein synthesis in cellular energy production.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- Mitochondrial translation synthesizes essential oxidative phosphorylation (OXPHOS) subunits.
- A quantitative understanding of mitoribosome traversal is crucial for cellular energy production.
Purpose of the Study:
- To develop high-resolution methods for delineating mammalian mitochondrial translation.
- To investigate the regulation and kinetics of mitochondrial translation flux.
- To explore the impact of mitochondrial tRNA modifications on translation.
Main Methods:
- Developed novel high-resolution mitochondrial ribosome profiling techniques.
- Utilized the translation inhibitor retapamulin to assess translation stoichiometry and kinetics.
- Analyzed effects of anticodon stem loop modifications in mitochondrial tRNAs (mt-tRNAs).
- Employed retapamulin-assisted profiling and mito-disome profiling.
Main Results:
- Revealed intricate regulation of mammalian mitochondrial translation.
- Quantified mitoribosome number, elongation, and initiation rates.
- Demonstrated the impact of mt-tRNA modifications on translation.
- Identified mitochondrial translation initiation factor (mtIF) 3-mediated initiation from internal ORFs.
- Mapped programmed mitoribosome collision sites.
Conclusions:
- The developed platform enables detailed investigation of mitochondrial protein synthesis.
- Provides insights into the regulation of OXPHOS subunit production.
- Highlights the role of mt-tRNA modifications and mtIF3 in mitochondrial translation.
Related Concept Videos
01:39Mitochondrial Protein Sorting
5.6K
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...
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
5.6K
01:19Translocation of Proteins into the Mitochondria
11.9K
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,...
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,...
11.9K
01:45Mitochondrial Membranes
16.6K
A single mitochondrion is a bean-shaped organelle enclosed by a double-membrane system. The outer membrane of mitochondria is smooth and contains many porins - the integral membrane transporters. Porins enable free diffusion of ions and small uncharged molecules through the outer mitochondrial membrane but limit the transport of molecules larger than 5000 Daltons. Further, the outer mitochondrial membrane forms a unique structure called membrane contact sites with other subcellular organelles,...
16.6K
02:07Improving Translational Accuracy
14.0K
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
14.0K
01:37Energy to Drive Translocation
2.6K
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
2.6K
01:12Porin Insertion in the Outer Mitochondrial Membrane
4.5K
Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
4.5K