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

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,...
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...
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...
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...

You might also read

Related Articles

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

Sort by
Same author

Uncovering the initial response: Intra-mitochondrial surveillance activates the UPR<sup>mt</sup>.

Molecular cell·2026
Same author

Orchestrating mitochondrial protein import: The emerging role of DYRK1A in health and disease.

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

How strong is a mitochondrial targeting signal?

The Journal of cell biology·2026
Same author

Mitochondria contact lipid droplets through the mitochondrial import complex binding to lipid metabolism enzyme Ayr1.

Nature cell biology·2026
Same author

Synthetic trap-peptides identify a TOM complex phosphatase - PP2A dephosphorylates Tom6.

The FEBS journal·2025
Same author

A screening approach unveils an unknown Mn<sup>2+</sup>-dependent endopolyphosphatase activity in yeast.

Chemical science·2025
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: May 26, 2026

Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy
07:26

Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy

Published on: July 29, 2019

Processing of mitochondrial presequences.

Dirk Mossmann1, Chris Meisinger, F-Nora Vögtle

  • 1Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung, Universität Freiburg, Freiburg, Germany.

Biochimica Et Biophysica Acta
|December 17, 2011
PubMed
Summary
This summary is machine-generated.

Mitochondrial proteins use targeting signals for import. Specific peptidases process these precursors, linking protein processing to mitochondrial dynamics and quality control.

More Related Videos

Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing
07:24

Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing

Published on: February 10, 2023

Methodology for Accurate Detection of Mitochondrial DNA Methylation
12:11

Methodology for Accurate Detection of Mitochondrial DNA Methylation

Published on: May 20, 2018

Related Experiment Videos

Last Updated: May 26, 2026

Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy
07:26

Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy

Published on: July 29, 2019

Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing
07:24

Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing

Published on: February 10, 2023

Methodology for Accurate Detection of Mitochondrial DNA Methylation
12:11

Methodology for Accurate Detection of Mitochondrial DNA Methylation

Published on: May 20, 2018

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Mitochondrial Biology

Background:

  • Mitochondrial proteins are synthesized as precursors on cytosolic or mitochondrial ribosomes.
  • These precursors contain targeting signals for organelle subcompartment delivery.
  • Nuclear- and mitochondrial-encoded proteins often utilize an N-terminal presequence for targeting.

Purpose of the Study:

  • To review the role of presequence peptidases in mitochondrial protein import and sorting.
  • To highlight the connection between precursor processing, mitochondrial dynamics, and protein quality control.

Main Methods:

  • Literature review of mitochondrial protein import and processing pathways.
  • Analysis of known and novel presequence peptidases.
  • Discussion of functional relevance in mitochondrial dynamics and quality control.

Main Results:

  • Mitochondrial protein precursors possess targeting signals, primarily N-terminal presequences.
  • Specific peptidases (MPP, IMP, Oct1, and novel proteases) cleave these presequences.
  • Precursor processing is functionally linked to mitochondrial dynamics and protein quality control.

Conclusions:

  • Presequence processing is crucial for accurate mitochondrial protein targeting and function.
  • Novel proteases expand our understanding of mitochondrial protein maturation.
  • The interplay between precursor processing, mitochondrial dynamics, and quality control is a key aspect of mitochondrial biology.