Contrary to belief, crucial protein for peripheral nerve repair is manufactured within the axon near the injury site
Several years ago, Prof. Michael Fainzilber and his group in the Biological Chemistry Department made a surprising discovery: Proteins thought to exist only near the cell nucleus could also be found in the far-off regions of the body's longest cells peripheral nerve cells that extend processes called axons, reaching up to a meter in length in adult humans.
These proteins, known as importins, have a well-studied role in the vicinity of the nucleus: They shuttle various molecules through the protective nuclear membrane. Fainzilber and his group showed that when a nerve cell is injured somewhere along its length, importins in the long axons hook into a sort of "railcar" mechanism, which then transports the "Help!" message from the injury site all the way to the nucleus.
These findings raised an intriguing question: How did importins get to the axons in the first place? Initial evidence suggested that one critical importin, called importin beta1, is produced locally upon injury near the site where it is needed. The problem was that years of scientific thinking on the subject indicated that proteins do not get manufactured in the axons, as investigations had turned up few of the cellular protein factories known as ribosomes there.
Settling the issue was far from simple: Importins are so crucial that even the smallest embryo could not survive without them. But Rotem Ben-Tov Perry, a joint research student in Fainzilber's group and that of department colleague Dr. Avraham Yaron, found a way to distinguish the importin beta1 in the cell body from that in the axon: The axonal protein was apparently made from a longer messenger RNA. To see if they could selectively affect just the axonal version of the protein, the groups, together with Prof. Jeff Twiss of Drexel University, Philadelphia, Pennsylvania, took advantage of high precision knock-out technology. Rather than knocking a whole gene out of the system, they managed to remove one little piece of the messenger RNA that carries the encoded instructions for manufacturing importins: just the longer bit that sends the RNA to the axon.
Now they observed plenty of importin beta1 in the cell body, but none in the axons. Mice with the knocked out segment of RNA took much longer to recover from peripheral nerve injury, and the genes that are normally active in response to nerve damage were activated to a lesser degree. All of this suggests that the importin beta1 that normally helps inform the extended nerve cell about injury is, indeed, produced locally in the axon.
Fainzilber: "The data shows conclusively that importin beta1 protein is produced in axons, and Rotem's work has validated the importins' crucial role in nerve repair." The findings, which appeared recently in Neuron, may help point the way toward better treatments for nerve damage and aid in finding ways to speed up the repair.
This video is not supported by your browser at this time.
Journal reference: Neuron
Provided by Weizmann Institute of Science
- Researchers identify protein required to regrow injured nerves in limbs Jun 20, 2012 | not rated yet | 0
- What makes an axon an axon? Nov 10, 2008 | not rated yet | 0
- Stress pathway identified as potential therapeutic target to prevent vision loss Feb 08, 2012 | not rated yet | 0
- New procedure repairs severed nerves in minutes, restoring limb use in days or weeks Feb 03, 2012 | not rated yet | 0
- Scientists discover a new line of communication between nervous system cells Jun 26, 2007 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
Marie Curie's leukemia
May 13, 2013 Does anyone know what might be the cause of Marie Curie's cancer
- More from Physics Forums - Medical Sciences
More news stories
For combat veterans suffering from post-traumatic stress disorder, 'fear circuitry' in the brain never rests
Chronic trauma can inflict lasting damage to brain regions associated with fear and anxiety. Previous imaging studies of people with post-traumatic stress disorder, or PTSD, have shown that these brain regions can over-or ...
Neuroscience May 18, 2013 | 5 / 5 (1) | 0 |
The neural machinery underlying our olfactory sense continues to be an enigma for neuroscience. A recent review in Neuron seeks to expand traditional ideas about how neurons in the olfactory bulb might encode information about ...
Neuroscience May 17, 2013 | 4 / 5 (1) | 0 |
(Medical Xpress)—What if the quality of your work depends more on your focus on the piano keys or canvas or laptop than your musical or painting or computing skills? If target users can be convinced, they ...
Neuroscience May 17, 2013 | 3.7 / 5 (3) | 0 |
Neurological disorders can have a devastating impact on the lives of sufferers and their families.
Neuroscience May 17, 2013 | 5 / 5 (1) | 0 |
If you're a left-brain thinker, chances are you use your right hand to hold your cell phone up to your right ear, according to a newly published study from Henry Ford Hospital in Detroit.
Neuroscience May 16, 2013 | 2 / 5 (2) | 0 |
When tumours metastasise, they can block lymphatic vessels, as researchers from ETH Zurich have discovered using a new method. The lymphatic fluid subsequently has to find a new path through the tissue. Such ...
30 minutes ago | not rated yet | 0 |
(Medical Xpress)—Flinders University researchers are breaking new ground in a decade-long journey to pinpoint the function of two closely related proteins.
20 minutes ago | not rated yet | 0 |
(Medical Xpress)—Scientists at King's College London have discovered that Vitamin D has the potential to significantly reduce the symptoms of asthma. The study, led by Professor Catherine Hawrylowicz from ...
9 minutes ago | not rated yet | 0 |
(Medical Xpress)—Patients with the most severe and dangerous form of chronic anorexia are more likely to make a significant improvement towards recovery and stay in therapy if traditional psychological treatments are re-focused ...
9 minutes ago | not rated yet | 0
Every 20 seconds, a limb is lost as a consequence of diabetic foot ulcer that does not heal. To date, medical solutions that can change this situation are very limited. In his doctoral thesis Yue Shen from the Industrial ...
29 minutes ago | not rated yet | 0
(Medical Xpress)—The feared Legionella pneumophila is responsible for legionellosis, an infectious disease that can lead to pneumonia. To infect humans, this pathogen has developed a complex method that allows it to camouflage ...
39 minutes ago | not rated yet | 0