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

ATP Synthase: Mechanism01:48

ATP Synthase: Mechanism

14.8K
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...
14.8K
Mitochondrial Membranes01:45

Mitochondrial Membranes

11.6K
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,...
11.6K
Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

2.6K
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...
2.6K
Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

3.1K
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...
3.1K
Structure of Porins01:21

Structure of Porins

3.0K
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
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

3.2K
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,...
3.2K

You might also read

Related Articles

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

Sort by
Same author

The impact of a three-dimensional interconnected continuity of care intervention on self-care capacity, negative emotional states, and quality of life in patients with ostomies.

Frontiers in public health·2026
Same author

Interaction of Bacterial Histidine Phosphatase SixA With Phosphocarrier Protein NPr and Phosphohistidine Analogs.

Journal of molecular biology·2026
Same author

Mechanism of isoleucyl-tRNA synthetase 2 regulating proliferation and apoptosis of cervical cancer cells.

Scientific reports·2026
Same author

Myosin IIA motor regulates attaching-effacing bacteria interactions with intestinal epithelium.

Gut microbes·2026
Same author

A single catalytic domain residue regulates the substrate specificity of a mucin-type O-glycosyltransferase in salivary gland function.

bioRxiv : the preprint server for biology·2026
Same author

Human <i>O-</i>GlcNAcase catalytic-stalk dimer anchors flexible histone binding domains.

Research square·2025

Related Experiment Video

Updated: Jul 18, 2025

Author Spotlight: Establishing a New Fluorescence-Based Protocol for In Vivo Mitochondrial Morphology Analysis in Parkinson's Disease
06:07

Author Spotlight: Establishing a New Fluorescence-Based Protocol for In Vivo Mitochondrial Morphology Analysis in Parkinson's Disease

Published on: June 23, 2023

1.6K

OPA1 helical structures give perspective to mitochondrial dysfunction.

Sarah B Nyenhuis1, Xufeng Wu2, Marie-Paule Strub3

  • 1Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA.

Nature
|August 23, 2023
PubMed
Summary

Dominant optic atrophy, a leading cause of childhood blindness, is linked to mutations in the OPA1 gene. This study reveals OPA1

More Related Videos

Author Spotlight: Decoding Mitochondrial Aging
08:48

Author Spotlight: Decoding Mitochondrial Aging

Published on: June 30, 2023

4.0K
Analysis of Brain Mitochondria Using Serial Block-Face Scanning Electron Microscopy
07:47

Analysis of Brain Mitochondria Using Serial Block-Face Scanning Electron Microscopy

Published on: July 9, 2016

14.1K

Related Experiment Videos

Last Updated: Jul 18, 2025

Author Spotlight: Establishing a New Fluorescence-Based Protocol for In Vivo Mitochondrial Morphology Analysis in Parkinson's Disease
06:07

Author Spotlight: Establishing a New Fluorescence-Based Protocol for In Vivo Mitochondrial Morphology Analysis in Parkinson's Disease

Published on: June 23, 2023

1.6K
Author Spotlight: Decoding Mitochondrial Aging
08:48

Author Spotlight: Decoding Mitochondrial Aging

Published on: June 30, 2023

4.0K
Analysis of Brain Mitochondria Using Serial Block-Face Scanning Electron Microscopy
07:47

Analysis of Brain Mitochondria Using Serial Block-Face Scanning Electron Microscopy

Published on: July 9, 2016

14.1K

Area of Science:

  • Mitochondrial biology
  • Structural biology
  • Genetics

Background:

  • Dominant optic atrophy (DOA) is a primary cause of childhood blindness.
  • Mutations in the optic atrophy protein 1 (OPA1) gene account for 60-80% of DOA cases.
  • OPA1 is essential for mitochondrial inner membrane fusion, cristae remodeling, and overall mitochondrial dynamics.

Purpose of the Study:

  • To elucidate the structural basis of OPA1 function and the impact of mutations.
  • To understand how OPA1 interacts with lipid membranes.

Main Methods:

  • Cryo-electron microscopy (cryo-EM) was used to determine the helical structures of OPA1.
  • Lipid membrane tubes were utilized to mimic OPA1's native environment.
  • Cell-based assays were employed to assess the functional consequences of mutations.

Main Results:

  • OPA1 forms densely packed helical assemblies on lipid membranes.
  • Nucleotide-dependent dimerization of OPA1 GTPase domains was observed, characteristic of the dynamin superfamily.
  • Unique secondary structures, including membrane-inserting helices, enhance OPA1's membrane association.
  • Pathogenic mutations disrupt OPA1 assembly interfaces and membrane binding, leading to mitochondrial fragmentation.

Conclusions:

  • The study reveals key structural features of OPA1 essential for its function in mitochondrial dynamics.
  • Structural insights explain how OPA1 mutations cause dominant optic atrophy.
  • Understanding these interactions is crucial for developing therapeutic strategies for OPA1-related optic neuropathies.