Related Experiment Video

Updated: Apr 26, 2026

Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria
09:01

Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria

Published on: January 7, 2022

2.3K

Exportability of the mitochondrial oxidative phosphorylation machinery into myelin sheath

Alessandro Morelli, Silvia Ravera, Daniela Calzia

    Theoretical Biology Forum
    |August 7, 2014
    PubMed

    Insights

    Mitochondria may assemble and export oxidative phosphorylation (OXPHOS) machinery to myelin sheaths. This export could enhance ATP production, supporting axonal survival and nervous system function.

    Area of Science:

    • Neuroscience
    • Cell Biology
    • Bioenergetics

    Background:

    • White matter's role in axonal survival is under review, as degeneration follows demyelination.
    • Myelin vesicles exhibit aerobic ATP production via mitochondrial Oxidative Phosphorylation (OXPHOS) machinery.
    • Mitochondrial genome-encoded OXPHOS subunits are found in myelin, suggesting export capability.

    Purpose of the Study:

    • To hypothesize that mitochondria are the sole site for OXPHOS assembly.
    • To propose that assembled OXPHOS is exported to energy-demanding cellular districts like myelin.
    • To suggest myelin's functional bioenergetic role in supplying ATP to axons.

    Main Methods:

    • Review of existing evidence on OXPHOS machinery in myelin.
    • Analysis of mitochondrial genome-encoded OXPHOS subunit expression in myelin.
    • Hypothetical modeling of OXPHOS assembly and export.

    Main Results:

    • OXPHOS machinery is present and functional in myelin vesicles, producing ATP.
    • Mitochondrial genome-encoded OXPHOS subunits in myelin are identical to those in the inner mitochondrial membrane.
    • This suggests OXPHOS is exportable from mitochondria.

    Conclusions:

    • Mitochondria are the unique site of OXPHOS assembly.
    • Exported OXPHOS to myelin may enhance ATP production efficiency.
    • Oligodendrocyte mitochondrial OXPHOS may be delivered to nascent myelin, supporting axonal bioenergetics and nervous conduction.

    More Related Videos

    Analyzing Mitochondrial Transport and Morphology in Human Induced Pluripotent Stem Cell-Derived Neurons in Hereditary Spastic Paraplegia07:32

    Analyzing Mitochondrial Transport and Morphology in Human Induced Pluripotent Stem Cell-Derived Neurons in Hereditary Spastic Paraplegia

    Published on: February 9, 2020

    7.3K
    Microfluidics-Assisted Selective Depolarization of Axonal Mitochondria06:55

    Microfluidics-Assisted Selective Depolarization of Axonal Mitochondria

    Published on: August 4, 2022

    1.7K

    Related Concept Videos

    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,...
    8.8K
    Energy to Drive Translocation01:37

    Energy to Drive Translocation

    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...
    2.0K
    Porin Insertion in the Outer Mitochondrial Membrane01:12

    Porin Insertion in the Outer Mitochondrial Membrane

    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...
    4.5K
    Export of Mitochondrial and Chloroplast Genes02:19

    Export of Mitochondrial and Chloroplast Genes

    A eukaryotic cell can have up to three different types of genetic systems: nuclear, mitochondrial, and chloroplast. During evolution, organelles have exported many genes to the nucleus; this transfer is still ongoing in some plant species. Approximately 18% of the Arabidopsis thaliana nuclear genome is thought to be derived from the chloroplast’s cyanobacterial ancestor, and around 75% of the yeast genome derived from the mitochondria’s bacterial ancestor. This export has occurred...
    3.1K
    Structure of Porins01:21

    Structure of Porins

    Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a  motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel...
    3.0K
    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...
    4.3K