During embryonic development, nerve cells form thin, long extensions, which they use to wire up a complex network, the brain. Scientists have now identified a protein that regulates the growth of these extensions by pulling a brake. In the long run, their findings could help to develop new approaches for the treatment of spinal cord injuries. The study is published in the journal Current Biology.
Neurons transmit electrical signals in a clearly defined direction - they are said to be "polarized". Each neuron receives signals and forwards them via a long extension, the so-called axon, to the next cell. In humans, axons in the spinal cord can become over a meter long. Is it possible to restimulate this impressive growth potential after spinal cord injuries? "To answer this question, we first need to better understand the molecular processes underpinning embryonic development," says the head of the study. They have now come a step closer to this goal by investigating neuronal growth in mice and cell culture.
At the center of the current study is a protein termed RhoA, a jack-of-all-trades among molecules. RhoA interacts with many protein partners and has different functions in a large variety of cells. However, its exact function in neurons had not yet been determined.
"For a long time it was thought that RhoA would determine the polarity of the neuron and thus select the position of axon formation in the cell," explains the senior author. The current study shows that this is not the case: RhoA has little to do with cell polarity and axon specification. Rather, RhoA comes into play only after the axon is formed and regulates its extension via a molecular cascade. This insight could be important for new therapies. "Manipulating the RhoA signaling pathway should thus only affect the growth of the nerve fibers without disturbing the cell's internal organization," says the author.
Like any other cell, neurons have a kind of skeleton that provides them with structure. The authors demonstrated that RhoA activates a molecular signaling pathway that directly targets the cytoskeleton. RhoA restrains axonal elongation by restricting the advancement of so-called microtubules - cytoskeletal building blocks necessary for axon stabilization - into the growth zone of the axon.
"In embryonic development, such a growth brake is probably necessary to coordinate different developmental processes. An accurate understanding of its molecular basis could now help to advance research on spinal cord regeneration after injury. To this end, the brake would need to be released," says the lead author of the study. "The molecular cascade we have identified directly influences the cytoskeleton of the axon and thus provides a good starting point for therapeutic strategies."
In a previous study, the team identified that a group of proteins - the "cofilin/ADF" family - also plays an important role for axon growth. Ultimately, both RhoA and the cofilin/ADF proteins act upon the axon's cytoskeleton, albeit in different ways. Both pathways could be potential targets for future therapies.
https://www.dzne.de/en/news/public-relations/press-releases/press/a-protein-that-pulls-the-brake-on-nerve-growth/
https://www.cell.com/current-biology/fulltext/S0960-9822(19)31231-X
http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Frhoa-controls-axon&filter=22
RhoA pulls the brake on nerve growth!
- 1,332 views
- Added
Edited
Latest News
Complete vascularization of…
By newseditor
Posted 28 Mar
Immune cells identified as…
By newseditor
Posted 28 Mar
TB blood test which could d…
By newseditor
Posted 27 Mar
Propionate supplementation…
By newseditor
Posted 27 Mar
Role of human Kallistatin i…
By newseditor
Posted 26 Mar
Other Top Stories
First successful treatment of mycobacterial lung infection with bac…
Read more
Biomaterial improves islet transplants for treatment of type 1 diab…
Read more
How deep brain stimulation treats Parkinson's disease symptoms
Read more
Plasma membrane phospholipid plays a key role in epithelial cell ad…
Read more
Stopping nervous system tumor growth in mice with an epilepsy drug
Read more
Protocols
Spatial proteomics in neuro…
By newseditor
Posted 28 Mar
All-optical presynaptic pla…
By newseditor
Posted 23 Mar
Epigenomic tomography for p…
By newseditor
Posted 20 Mar
A mouse DRG genetic toolkit…
By newseditor
Posted 17 Mar
An optogenetic method for t…
By newseditor
Posted 13 Mar
Publications
A microfluidic platform int…
By newseditor
Posted 28 Mar
Salmonella manipulates macr…
By newseditor
Posted 28 Mar
BHLHE40/41 regulate microgl…
By newseditor
Posted 28 Mar
Balancing neuronal activity…
By newseditor
Posted 28 Mar
OSBP-mediated PI(4)P-choles…
By newseditor
Posted 28 Mar
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar