Nav: Home

Cell type and environment influence protein turnover in the brain

June 19, 2018

Scientists have revealed that protein molecules in the brain are broken down and replaced at different rates, depending on where in the brain they are.

The study, published in eLife, provides essential insights into how the components of different cells in the brain are altered. These kinds of alterations may be important in our abilities to learn and form memories, especially as protein turnover plays a crucial role in these processes.

Proteins are the mechanical engines of the cell, carrying out many essential functions. The 'turnover' of proteins in a cell is balanced by how much protein is manufactured and how much is broken down. Under normal conditions, this turnover is continuous, and ensures that damaged proteins can be removed and replaced by new ones. It also gives a cell the ability to change its entire proteome - all the proteins it contains - to respond quickly to internal and external signals, such as hormones or electrical impulses.

Protein turnover ensures that synapses - the structures that allow an electrical or chemical impulse from one nerve cell to another - remain flexible. This phenomenon, called 'synaptic plasticity', is important for maintaining the brain's ability to create new nerve networks, which in turn allows us to create new memories or learn new behaviours and skills.

"It is known that proteins can show very different turnover rates in different tissues or different cell types of the same organism, but little is known about protein turnover rates in different cell types of the brain, and how they affect each other," explains lead author Aline Dörrbaum, graduate student at the Max Planck Institute for Brain Research, Germany.

To address this, the team grew cells from the hippocampus region of the brain and used isotopically labelled amino acids (the building blocks of proteins) to determine the 'half-life' of proteins. This was measured by how quickly the 'heavy'-labelled proteins appeared in the cells as the proteins were made, and how quickly the natural 'light' proteins disappeared as they were broken down. The team obtained half-life measurements for over 5,100 protein groups from different neuronal culture types that contained a mixture of neurons and glia cells (which support and provide insulation between neurons). All samples contained both neurons and glia cells, but in different proportions.

They found the half-lives varied greatly - from less than a day (fast turnover) to more than 20 days (slow turnover) - and that this depended on the location of the protein in the cell. Proteins nearer the surface of the cell, often involved in communication, were shorter-lived and proteins involved in energy metabolism were longer-lived compared to the overall protein population.

Of particular note, the researchers found that an identical protein expressed in glia cells had a much faster turnover rate than when it was expressed in neuron cells. A subset of proteins also had faster or slower turnover rates when there were more glial cells in the environment.

"Our results demonstrate that both the cell-type of origin as well as the nature of the environment outside the cell have powerful influences on protein turnover," concludes senior author Professor Erin Schuman, Director of the Max Planck Institute for Brain Research. "Our next goal is to determine how nerve plasticity regulates and exploits turnover to modify the brain proteomes in response to different stimuli."
-end-
Reference

The paper 'Local and global influences on protein turnover in neurons and glia' can be freely accessed online at https://doi.org/10.7554/eLife.34202. Contents, including text, figures and data, are free to reuse under a CC BY 4.0 license.

Media contact

Emily Packer, Senior Press Officer
eLife
e.packer@elifesciences.org
01223 855373

About eLife

eLife aims to help scientists accelerate discovery by operating a platform for research communication that encourages and recognises the most responsible behaviours in science. We publish important research in all areas of the life and biomedical sciences, which is selected and evaluated by working scientists and made freely available online without delay. eLife also invests in innovation through open source tool development to accelerate research communication and discovery. Our work is guided by the communities we serve. eLife is supported by the Howard Hughes Medical Institute, the Max Planck Society, the Wellcome Trust and the Knut and Alice Wallenberg Foundation. Learn more at https://elifesciences.org.

eLife

Related Neurons Articles:

How do we get so many different types of neurons in our brain?
SMU (Southern Methodist University) researchers have discovered another layer of complexity in gene expression, which could help explain how we're able to have so many billions of neurons in our brain.
These neurons affect how much you do, or don't, want to eat
University of Arizona researchers have identified a network of neurons that coordinate with other brain regions to influence eating behaviors.
Mood neurons mature during adolescence
Researchers have discovered a mysterious group of neurons in the amygdala -- a key center for emotional processing in the brain -- that stay in an immature, prenatal developmental state throughout childhood.
Astrocytes protect neurons from toxic buildup
Neurons off-load toxic by-products to astrocytes, which process and recycle them.
Connecting neurons in the brain
Leuven researchers uncover new mechanisms of brain development that determine when, where and how strongly distinct brain cells interconnect.
The salt-craving neurons
Pass the potato chips, please! New research discovers neural circuits that regulate craving and satiation for salty tastes.
When neurons are out of shape, antidepressants may not work
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed medication for major depressive disorder (MDD), yet scientists still do not understand why the treatment does not work in nearly thirty percent of patients with MDD.
Losing neurons can sometimes not be that bad
Current thinking about Alzheimer's disease is that neuronal cell death in the brain is to blame for the cognitive havoc caused by the disease.
Neurons that fire together, don't always wire together
As the adage goes 'neurons that fire together, wire together,' but a new paper published today in Neuron demonstrates that, in addition to response similarity, projection target also constrains local connectivity.
Scientists accidentally reprogram mature mouse GABA neurons into dopaminergic-like neurons
Attempting to make dopamine-producing neurons out of glial cells in mouse brains, a group of researchers instead converted mature inhibitory neurons into dopaminergic cells.
More Neurons News and Neurons Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Accessing Better Health
Essential health care is a right, not a privilege ... or is it? This hour, TED speakers explore how we can give everyone access to a healthier way of life, despite who you are or where you live. Guests include physician Raj Panjabi, former NYC health commissioner Mary Bassett, researcher Michael Hendryx, and neuroscientist Rachel Wurzman.
Now Playing: Science for the People

#544 Prosperity Without Growth
The societies we live in are organised around growth, objects, and driving forward a constantly expanding economy as benchmarks of success and prosperity. But this growing consumption at all costs is at odds with our understanding of what our planet can support. How do we lower the environmental impact of economic activity? How do we redefine success and prosperity separate from GDP, which politicians and governments have focused on for decades? We speak with ecological economist Tim Jackson, Professor of Sustainable Development at the University of Surrey, Director of the Centre for the Understanding of Sustainable Propserity, and author of...
Now Playing: Radiolab

An Announcement from Radiolab