Navigation Links
MDC researchers discover molecule responsible for axonal branching
Date:9/21/2009

The human brain consists of about 100 billion (1011) neurons, which altogether form about 100 trillion (1014) synaptic connections with each other. A crucial mechanism for the generation of this complex wiring pattern is the formation of neuronal branches. The neurobiologists Dr. Hannes Schmidt and Professor Fritz G. Rathjen at the Max Delbrck Center for Molecular Medicine (MDC) Berlin-Buch, Germany, have now discovered a molecule that regulates this vital process. At the same time they have succeeded in elucidating the signaling cascade induced by this molecule (PNAS, Early Edition, 2009, doi:10.1073)*.

Through the ramification of its fiber-like axon, a single neuron can send branches and thus transmit information into several target areas at the same time. In principle, neurobiologists distinguish between two kinds of axonal branching: branching of the growth cone at the tip of an axon and the sprouting of collaterals (interstitial branching) from the axon shaft.

Both forms of axonal branching can be observed in sensory neurons, which transmit the sensation of touch, pain and temperature, among others. When the axons of these neurons reach the spinal cord, their growth cones first split (bifurcate) and consequently the axons divide into two branches growing in opposite directions. Later new branches sprout from the shaft of these daughter axons which penetrate the gray matter of the spinal cord.

Through investigations on sensory neurons, Dr. Hannes Schmidt and his colleagues were able to identify a protein which triggers the splitting of the growth cone of the sensory axons: the peptide CNP (the abbreviation stands for C-type natriuretic peptide). In transgenic mice the scientists were able to show that CNP is formed in the spinal cord precisely when sensory neurons grow into it. In the absence of CNP bifurcation can no longer occur which results in reduced neuronal connectivity in the spinal cord.

The new findings supplement earlier discoveries of the research group of Professor Rathjen according to which a cGMP-signaling cascade is responsible for the bifurcation of sensory axons. When CNP binds to its receptor Npr2 (natriuretic peptide receptor 2) on the surface of the axons, this signaling cascade is set in motion, which in turn induces the formation of the secondary messenger molecule cGMP. This messenger molecule then activates the protein kinase cGKI (cGMP-dependent protein kinase I), which can switch on and off a whole series of target proteins. The cytoskeleton of the neurons is thus altered in such a way that their growth cone splits into two daughter axons.

Next, the researchers want to identify these target proteins. Further analyses should clarify whether the cGMP signaling cascade likewise regulates the branching of other axon systems and whether this impacts the sensation of pain.


'/>"/>

Contact: Barbara Bachtler
bachtler@mdc-berlin.de
49-309-406-3896
Helmholtz Association of German Research Centres
Source:Eurekalert

Related biology news :

1. Researchers identify proteins involved in new neurodegenerative syndrome
2. Texas researchers and educators head for Antarctica
3. MGH researchers describe new way to identify, evolve novel enzymes
4. University of Pennsylvania researchers develop formula to gauge risk of disease clusters
5. U of MN researchers discover noninvasive diagnostic tool for brain diseases
6. U of Minnesota researchers discover noninvasive diagnostic tool for brain diseases
7. Researchers discover new strategies for antibiotic resistance
8. Researchers find new taste in fruit flies: carbonated water
9. Binghamton University researchers investigate evolving malaria resistance
10. UIC researchers find promising new targets for antibiotics
11. Researchers develop simple method to create natural drug products
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/11/2017)... MOINES, Iowa , Jan. 11, 2017 ... industry first with the release of its patent-pending calibration ... quickly and reliably perform calibrations, securely upload data logs ... flexibility for the customer. "Fighting drunk driving ... only for the public at large, but also for ...
(Date:1/6/2017)... 2017  SomaLogic announced today that it has ... by iCarbonX, the China -based ... Digital Health Ecosystem that can define each person,s ... biological, behavioral and psychological data, the Internet and ... SomaLogic will provide proteomics data and applications expertise ...
(Date:1/4/2017)... VEGAS , Jan. 4, 2017  CES ... performance biometric sensor technology, today announced the launch ... sensor systems, the highly-accurate biometric sensor modules ... biometric technology, experience and expertise. The two ... Benchmark designed specifically for hearables, and Benchmark BW2.0, ...
Breaking Biology News(10 mins):
(Date:1/21/2017)...   Boston Biomedical , an industry leader in ... stemness pathways, today presented data from two clinical studies ... American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium ... In a Phase Ib/II study of napabucasin – ... stemness pathways by targeting STAT3 – colorectal cancer (CRC) ...
(Date:1/20/2017)... Stock-Callers.com explores the Biotech industry ... most recent performances of select equities. In this morning,s ... ), Abeona Therapeutics Inc. (NASDAQ: ABEO ), ... Sage Therapeutics Inc. (NASDAQ: SAGE ). According ... global Biotech market size is expected to reach $604.40 billion by 2020 due ...
(Date:1/20/2017)... NEW YORK , January 20, 2017 ... Health Organization, cancer is one of leading causes of ... in 2012. Although the number of cancer related deaths ... since 1990. Rising in incidence rate of various cancers ... According to a research report by Global Market Insights, ...
(Date:1/19/2017)... Research and Markets has announced the addition of the ... Global Opportunity Analysis and Industry Forecast, 2014-2022" report to their ... Cancer ... reach $15,737 million by 2022 from $6,521 in 2015, growing at ... Omic technologies segment accounted for more than half of the revenue ...
Breaking Biology Technology: