AUG 07, 2017 6:32 PM PDT

New Details on Protein Recycling in the Brain

WRITTEN BY: Carmen Leitch

Our cells are good at recycling; they maintain a balance between the production of new material and the degradation of old or unneeded stuff. A specialized organelle in the cell called a lysosome is a critical part of this process. They contain around 50 different digestive enzymes that act like a digestive system for the cell, ridding it of what’s useless and breaking down complex molecules.

Lysosomes were identified in dendrites and dendritic spines using various techniques. Cultured neurons show lysosomes throughout neurons and in dendritic spines indicated in yellow (left and upper right); brain slices show a lysosome in the head of the spine highlighted in green (middle right); and transmission electron microscopy reveals a lysosome (black circle) near the base of a spine (bottom right). / Credit: Marisa Goo, Gentry Patrick/UCSD/Journal of Cell Biology

This process is especially important in the human brain, where tight control helps ensure that all is well with learning and memory. When the system becomes defective, serious disease can occur. Lysosomal dysfunction has been connected to both Parkinson's and Alzheimer's diseases.

New work by researchers including graduate student Marisa Goo and Professor Gentry Patrick at the University of California San Diego has shown for the first time that lysosomes are able to travel throughout neurons, reaching distant branches at one end of the cell called dendrites. The research is outlined in the video below and has been reported in the Journal of Cell Biology.

The scientists were surprised to find that lysosomes can migrate to dendritic spines, areas that are critical to nerve cell signaling. Additionally, the investigators learned that when a single dendritic spine is activated, lysosomes can be directly recruited to these very specific parts of the neuron.

"Previously there was no reason to think that lysosomes could travel out to the ends of dendrites at synapses," explained Patrick, who is a Professor of Neurobiology in the Division of Biological Sciences at UC San Diego. "We are showing neuronal activity is delivering them to the synapse and they are playing an integral and instructive role in remodeling and plasticity, which are so important for learning and memory."

By using genetic techniques to attach fluorescent markers highlighting lysosomes, the researchers followed the movement of the organelles around the cell. At times they were found to be hundreds of microns away from the cell body, a central part of the neuron where it had been thought lysosomes normally resided. Various microscopy techniques -- confocal, electron and two-photon -- showed how lysosomes can travel to a precise part of the dendrites under normal conditions, a previously unknown phenomenon.

"We've shown that lysosomes can be recruited to a single synapse... until now we had no idea that lysosomes could receive such instructive cues," explained Patrick, "For many neurodegenerative diseases, lysosome dysfunction seems to play a role. So now we can look at the distribution and trafficking of lysosomes - which we now know are controlled by neurons - and ask: Is that altered in disease?"

 

Sources: AAAS/Eurekalert! Via UCSD, Biochemical Society Transactions, Movement Disorders, Journal of Cell Biology

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
APR 21, 2021
Microbiology
An Unknown Unknown - What's the State of Microbial Biodiversity?
APR 21, 2021
An Unknown Unknown - What's the State of Microbial Biodiversity?
Researchers have noted that we have a 'profound ignorance' about the state of the microbial populations of the world.
APR 25, 2021
Microbiology
Plant-Eating Microbes Expand the Tree of Life
APR 25, 2021
Plant-Eating Microbes Expand the Tree of Life
After microbes called archaea were discovered in the 1970s, a branch was added to the tree of life after some debate, wh ...
MAY 13, 2021
Genetics & Genomics
Explore Ways to Enhance Biomarker Discovery Research
MAY 13, 2021
Explore Ways to Enhance Biomarker Discovery Research
Enhance your existing research or discover new methods with a suite of NGS tools and techniques to find and characterize ...
MAY 20, 2021
Genetics & Genomics
The rhAmpSeq™ CRISPR Analysis System for next-generation sequencing analysis of CRISPR edits
MAY 20, 2021
The rhAmpSeq™ CRISPR Analysis System for next-generation sequencing analysis of CRISPR edits
CRISPR genome editing generates double-stranded breaks (DSBs) in genomic DNA and is a targeted method by which to achiev ...
JUN 03, 2021
Microbiology
How HIV Can Deplete White Matter in the Brain
JUN 03, 2021
How HIV Can Deplete White Matter in the Brain
The brain is sometimes called grey matter, which is made up of neurons. But it also contains white matter, which are neu ...
JUN 09, 2021
Cell & Molecular Biology
Mechanism Linking Neurodegeneration & Brain Injury May Open Treatment Options
JUN 09, 2021
Mechanism Linking Neurodegeneration & Brain Injury May Open Treatment Options
Studies have shown that there is a link between blows to the head and neurodegeneration. Repeated head trauma is associa ...
Loading Comments...