Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Protein Transport into the Inner Mitochondrial Membrane01:34

Protein Transport into the Inner Mitochondrial Membrane

Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
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...
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 precursors...
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,...
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...
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 precursors...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

YhbO is a DJ-1 family glyoxalase and α-oxoaldehyde hydratase that confers resistance to reactive carbonyl stress (112).

The Journal of biological chemistry·2026
Same author

BCAS-3 is required for the progression of autophagosome formation to degrade paternal mitochondria in <i>Caenorhabditis elegans</i>.

iScience·2026
Same author

Epigenomic profiling of neuroendocrine lung cancers identifies a classical-neuroendocrine ASCL1/NKX2-1 subtype and a SOX11-associated differentiation axis linked to reduced immunogenicity.

Lung cancer (Amsterdam, Netherlands)·2026
Same author

How membranes shape up for lipid transfer.

eLife·2026
Same author

Mitochondrially tethered Mmm1 can function as a sole lipid transporter at ER-mitochondria contacts.

The Journal of cell biology·2026
Same author

Proteostasis at the mitochondrial outer membrane: Quality control of mitochondrial protein transport.

Protein science : a publication of the Protein Society·2026
Same journal

Cumulative Contents.

Biochimica et biophysica acta·2020
Same journal

Molecular Basis of Disease Cumulative Contents.

Biochimica et biophysica acta·2020
Same journal

General Subjects Cumulative Contents.

Biochimica et biophysica acta·2020
Same journal

Erratum to 'on the role of exchangeable hydrogen bonds for the kinetics of P680<sup>+·</sup> Q<sub>A</sub> <sup>-·</sup> formation and P680<sup>+·</sup> Pheo<sup>-·</sup> recombination in photosystem II' [Biochim. Biophys. Acta 1276 (1996) 35-44].

Biochimica et biophysica acta·2019
Same journal

Oligomeric state of the light-harvesting complexes B800-850 and B875 from purple bacterium Rubrivivax gelatinosus in detergent solution.

Biochimica et biophysica acta·2019
Same journal

Regulation of pigment content and enzyme activity in the cyanobacterium Nostoc sp. Mac grown in continuous light, a light-dark photoperiod, or darkness.

Biochimica et biophysica acta·2019
See all related articles

Related Experiment Video

Updated: Jun 10, 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

Structural insight into the mitochondrial protein import system.

Toshiya Endo1, Koji Yamano, Shin Kawano

  • 1Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan. endo@biochem.chem.nagoya-u.ac.jp

Biochimica Et Biophysica Acta
|July 27, 2010
PubMed
Summary
This summary is machine-generated.

Mitochondrial protein transport is crucial for cell function, involving a complex import system. Recent high-resolution structures reveal molecular mechanisms of this essential process.

More Related Videos

Rapid Isolation of the Mitoribosome from HEK Cells
09:33

Rapid Isolation of the Mitoribosome from HEK Cells

Published on: October 4, 2018

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae
08:55

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae

Published on: July 19, 2021

Related Experiment Videos

Last Updated: Jun 10, 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

Rapid Isolation of the Mitoribosome from HEK Cells
09:33

Rapid Isolation of the Mitoribosome from HEK Cells

Published on: October 4, 2018

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae
08:55

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae

Published on: July 19, 2021

Area of Science:

  • Biochemistry and Molecular Biology
  • Cell Biology
  • Structural Biology

Background:

  • Mitochondria require precise transport of 1000-1500 proteins for proper function.
  • This transport is facilitated by a sophisticated mitochondrial protein import system.
  • This system involves translocators and soluble factors across mitochondrial membranes.

Purpose of the Study:

  • To review high-resolution structures of mitochondrial protein import machinery components.
  • To provide structural and mechanistic insights into mitochondrial protein transport.
  • To advance the understanding of molecular mechanisms governing mitochondrial protein import.

Main Methods:

  • Review of recently available high-resolution structural data.
  • Analysis of structural components of the mitochondrial protein import system.
  • Integration of structural information with mechanistic understanding of protein transport.

Main Results:

  • Availability of high-resolution structures for key components of the import machinery.
  • Structural insights into the function of translocators and soluble factors.
  • Enhanced understanding of the molecular basis of mitochondrial protein targeting and translocation.

Conclusions:

  • High-resolution structures have significantly advanced the understanding of mitochondrial protein import.
  • Structural biology provides critical mechanistic details of the mitochondrial protein transport system.
  • Continued structural studies will further elucidate the intricacies of mitochondrial protein biogenesis.