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

Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

4.3K
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...
4.3K
The Inner Mitochondrial Membrane01:28

The Inner Mitochondrial Membrane

4.4K
The inner mitochondrial membrane is the primary site of ATP synthesis. The inner membrane domain that forms a smooth layer adjacent to the outer membrane is called the inner boundary membrane. This domain contains membrane transporters that drive metabolites in and out of the mitochondria.  In contrast, the inner membrane network that invaginates into the matrix space is called the cristae membrane. This domain accounts for principle mitochondrial function as it accommodates the protein...
4.4K
Protein Transport into the Inner Mitochondrial Membrane01:34

Protein Transport into the Inner Mitochondrial Membrane

4.7K
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...
4.7K
Structure of Porins01:21

Structure of Porins

3.7K
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...
3.7K
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

11.7K
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,...
11.7K
Mitochondrial Protein Sorting01:39

Mitochondrial Protein Sorting

5.5K
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...
5.5K

You might also read

Related Articles

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

Sort by
Same author

Phenylalanine intercalation parameters for liquid-disordered phase domains - a membrane model study.

BMC biophysics·2018
Same author

Cytochrome-c-assisted escape of cardiolipin from a model mitochondrial membrane.

Biochimica et biophysica acta. Biomembranes·2017
Same author

Coexisting phases in PEGylated phosphocholine membranes: a model study.

Langmuir : the ACS journal of surfaces and colloids·2012
Same author

Effect of saline on transitions in poly(ethylene glycol)-grafted succinyl-phosphoethanolamine monolayers bearing C16 aliphatic chains.

The journal of physical chemistry. B·2011
Same author

Lateral distribution of a poly(ethylene glycol)-grafted phospholipid in phosphocholine monolayers studied by epifluorescence microscopy.

Langmuir : the ACS journal of surfaces and colloids·2008
Same author

Mixing behavior of a poly(ethylene glycol)-grafted phospholipid in monolayers at the air/water interface.

Langmuir : the ACS journal of surfaces and colloids·2008

Related Experiment Video

Updated: Dec 29, 2025

A Model Membrane Platform for Reconstituting Mitochondrial Membrane Dynamics
10:31

A Model Membrane Platform for Reconstituting Mitochondrial Membrane Dynamics

Published on: September 2, 2020

8.0K

Acylcarnitines at the Membrane Surface: Insertion Parameters for a Mitochondrial Leaflet Model.

Wajih Anwer1, Amanda Ratto Velasquez1, Valeria Tsoukanova1

  • 1Department of Chemistry, York University, Toronto, Ontario, Canada.

Biophysical Journal
|February 7, 2020
PubMed
Summary

Excessive acylcarnitines (ACs) accumulate in metabolic disorders. Research shows ACs insert into mitochondrial membranes via their acyl chains, potentially altering membrane function and contributing to disease.

More Related Videos

Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools
05:27

Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools

Published on: July 20, 2022

2.2K
F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes
08:21

F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes

Published on: May 4, 2013

10.8K

Related Experiment Videos

Last Updated: Dec 29, 2025

A Model Membrane Platform for Reconstituting Mitochondrial Membrane Dynamics
10:31

A Model Membrane Platform for Reconstituting Mitochondrial Membrane Dynamics

Published on: September 2, 2020

8.0K
Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools
05:27

Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools

Published on: July 20, 2022

2.2K
F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes
08:21

F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes

Published on: May 4, 2013

10.8K

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cellular Physiology

Background:

  • Elevated acylcarnitines (ACs) are linked to metabolic disorders like obesity and insulin resistance.
  • The precise mechanisms by which ACs contribute to these pathophysiological effects are not well understood.
  • Investigating AC interactions with mitochondrial membranes is crucial for understanding their role in disease.

Purpose of the Study:

  • To elucidate the interaction mechanisms between acylcarnitines and the mitochondrial inner membrane.
  • To model the outer leaflet of the mitochondrial inner membrane to study AC insertion.
  • To determine the parameters and consequences of AC insertion into the membrane.

Main Methods:

  • Utilized Langmuir monolayers and cushioned supported bilayers to model the mitochondrial inner membrane's outer leaflet.
  • Employed epifluorescence microscopy to observe AC interactions and leaflet changes.
  • Performed constant-pressure insertion assays to quantify AC insertion parameters.

Main Results:

  • Observed local leaflet expansion upon exposure to long-chain ACs, indicating insertion.
  • Determined that AC insertion involves primarily the acyl chain (21 ± 3 Ų), leaving the carnitine moiety exposed.
  • Found the carnitine moiety requires a larger area (37 ± 3 Ų) and likely alters surface electrostatics.

Conclusions:

  • Acylcarnitine insertion into mitochondrial membranes occurs primarily via the acyl chain.
  • This insertion alters membrane morphology and surface electrostatics, particularly with long-chain ACs.
  • ACs may trigger signaling pathways in the inner mitochondrial membrane, contributing to pathophysiological outcomes.