NOV 01, 2016 1:26 PM PDT

New Details of Mitochondrial Division Revealed

WRITTEN BY: Carmen Leitch
Cells are divided into organelles that help accomplish all of the various tasks of a cell. One organelle, the mitochondria, is crucially important as the powerhouse of the cell, generating the necessary energy for functioning. New work from a University of Colorado Boulder laboratory that has previously done research in this area has revealed the final stages of mitochondrial replication and division.
 
Electron tomography reveals the 3D structure of membrane contact sites (colored red) between ER tubules (green) and mitochondria (purple) in a yeast cell (right) or an endosome (yellow) in an animal cell (left)./ Credit: Matthew West.

Back in 2011, these investigators demonstrated how another organelle called the endoplasmic reticulum (ER) makes a web through the cytoplasm of a cell, which encircles other organelles including the mitochondria. Their research showed that when a branch of the ER touches individual mitochondria and starts constriction, a protein called dynamin-related protein, Drp1, is called to the site to constrict the mitochondria even more where the ER is touching it.

In their new study, published in the journal Nature, the researchers report that once Drp1 starts squeezing the mitochondria, another protein comes to finish the job. That protein, Dynamin 2 or Dyn2, completes the process of fission, in which the organelle is split into two parts. The dynamin proteins are shaped like coils that surround the mitochondria and constrict like a person twisting a balloon.

These proteins work together; it seems that Drp1 puts the squeeze on the mitochondria to compact it, then Dyn2 moves when the constriction coil is small enough and finishes the process.

"Our findings change what everyone has believed about mitochondrial division," explained the first author of the study, postdoctoral fellow Jason Lee. "Now we know that it takes at least three different constriction steps in order to ultimately divide mitochondria."

Mitochondria contain their own DNA, which is passed down maternally. In any given cell, depending on the energy requirements of the cell type, there may be only a few mitochondria or there may be several thousand. When cells have additional energy needs, they can create more mitochondria.
 


Mitochondria, discussed in the video above, play many vital roles in the cell. Beyond being a source of energy, they have an influence on longevity; they are critical to the maintenance of blood sugar and fat. Mitochondrial dysfunction can have an impact on a wide variety of organ systems including the brain, liver, skeletal muscles, heart and respiratory systems.

A better understanding of how they replicate and divide puts us a little bit closer to understanding how pathological conditions like cancer cause changes and disorders inside of cells, Wu commented.
"The ability of our cells to efficiently convert nutrients into energy is rooted in the cell's ability to manage the shape, number and positioning of mitochondria through a balance of fusion and division," continued Lee. "This balance goes awry in cancer and neurodegeneration."

Sources: AAAS/Eurekalert! via University of Colorado Boulder, Nature
 
About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 15, 2020
Cell & Molecular Biology
Autism Spectrum Disorder Biomarker is Discovered
SEP 15, 2020
Autism Spectrum Disorder Biomarker is Discovered
Scientists may have identified a biomarker for autism spectrum disorder, which can be difficult to differentiate from ot ...
OCT 19, 2020
Clinical & Molecular DX
Making Capillary Electrophoresis Accessible for Any Lab
OCT 19, 2020
Making Capillary Electrophoresis Accessible for Any Lab
Analyzing nucleic acids through gel electrophoresis has been a staple of genetic research for decades. But using traditi ...
OCT 06, 2020
Cell & Molecular Biology
How a Carnivorous Plant Creates a 'Memory'
OCT 06, 2020
How a Carnivorous Plant Creates a 'Memory'
The Venus flytrap (Dionaea muscipula) is a famous carnivorous plant that can capture and consume insects and even small ...
OCT 08, 2020
Immunology
Immuno Metabolic Complexity and Modulating Metabolites
OCT 08, 2020
Immuno Metabolic Complexity and Modulating Metabolites
Immunometabolism is a relatively new subspecialty of immunology as we’ve begun to unravel the complex metabolic re ...
NOV 16, 2020
Genetics & Genomics
Hidden Genes in the SARS-CoV-2 Genome
NOV 16, 2020
Hidden Genes in the SARS-CoV-2 Genome
It's essential for organisms to use their genomes to make proteins, and the processes of transcription and translation a ...
NOV 27, 2020
Genetics & Genomics
Gravity Affects Gene Expression
NOV 27, 2020
Gravity Affects Gene Expression
If people are going to explore deep space, we should learn more about the effects that such an environment would potenti ...
Loading Comments...