Featured Research

from universities, journals, and other organizations

Scientists reveal new survival mechanism for neurons

Date:
August 31, 2011
Source:
Johns Hopkins Medical Institutions
Summary:
Nerve cells that regulate everything from heart muscle to salivary glands send out projections known as axons to their targets. By way of these axonal processes, neurons control target function and receive molecular signals from targets that return to the cell body to support cell survival. Now, researchers have revealed a molecular mechanism that allows a signal from the target to return to the cell body and fulfill its neuron-sustaining mission.

Nerve cells that regulate everything from heart muscle to salivary glands send out projections known as axons to their targets. By way of these axonal processes, neurons control target function and receive molecular signals from targets that return to the cell body to support cell survival. Now, Johns Hopkins researchers have revealed a molecular mechanism that allows a signal from the target to return to the cell body and fulfill its neuron-sustaining mission.

Related Articles


The discovery, reported August 5 in the journal Cell, reveals that the activated protein Rac, a key component of signals that make it all the way back to home base, is absent in signals that don't return to the cell body.

"Defective transport processes along axons may be contributing factors in a variety of neurodegenerative diseases, such as ALS, Parkinson's and Alzheimer's," says David Ginty, Ph.D., a professor in The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, and an investigator of the Howard Hughes Medical Institute. "By comparing signals that make it all the way back to the cell body with those that cannot, we gain an appreciation of the workings of the microtubule network inside of axons and the mechanisms of retrograde transport of key neuronal survival signals."

Using mouse neurons from ganglia that line the spinal column, the scientists figured out the signal known as nerve growth factor (NGF), which is made in the target field and travels along the axon to the command center of the cell, the cell body. Separately they found that a related signal known as NT3, which, though it helps axons grow along their intermediate targets, doesn't support travel of a survival signal back to the cell body.

The team then analyzed all the protein components of NGF signaling for the purpose of pinpointing the key component that supports long-range signaling and neuronal survival. Present in NGF signals, yet conspicuously missing from NT3, was Rac, a protein that regulates components of the cytoskeletal roadway along which molecular machinery assembles cargo to be moved up the axon toward a target tissue or back down to the cell body.

In a series of experiments using mouse neurons in special dishes with separate chambers through which axons could extend and be treated with different growth factors, the team added an active form of Rac to the NT3 signals and saw that this was enough to coax them back to the cell body and deliver cell survival messages. Next, they removed Rac from the NGF signal and showed that its elimination prevented it from making the trip to the cell body and supporting survival.

Because neurons die in mice that are engineered to lack either NT3 or NGF, conventional wisdom held that both NFG and NT3 are so-called survival factors. This new work reveals an important if subtle distinction between the two by showing how and why NGF -but not NT3 -- is capable of making the long trip to the cell body to support neuron survival.

Support for this research came from the National Institutes of Health and The Silvio Conte Center for Neuroscience Research.

Authors from Johns Hopkins, in addition to Ginty, are Anthony W. Harrington, Coryse St. Hillaire, Larry S. Zweifel and Natalia O. Glebova. Also, from the State University of New York at Stony Brook are Polyxeni Philippidou and Simon Halegoua.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Journal Reference:

  1. AnthonyW. Harrington, Coryse St.Hillaire, LarryS. Zweifel, NataliaO. Glebova, Polyxeni Philippidou, Simon Halegoua, DavidD. Ginty. Recruitment of Actin Modifiers to TrkA Endosomes Governs Retrograde NGF Signaling and Survival. Cell, 2011; 146 (3): 421 DOI: 10.1016/j.cell.2011.07.008

Cite This Page:

Johns Hopkins Medical Institutions. "Scientists reveal new survival mechanism for neurons." ScienceDaily. ScienceDaily, 31 August 2011. <www.sciencedaily.com/releases/2011/08/110831093947.htm>.
Johns Hopkins Medical Institutions. (2011, August 31). Scientists reveal new survival mechanism for neurons. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2011/08/110831093947.htm
Johns Hopkins Medical Institutions. "Scientists reveal new survival mechanism for neurons." ScienceDaily. www.sciencedaily.com/releases/2011/08/110831093947.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Hugging It Out Could Help You Ward Off A Cold

Hugging It Out Could Help You Ward Off A Cold

Newsy (Dec. 21, 2014) Carnegie Mellon researchers found frequent hugs can help people avoid stress-related illnesses. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins