 |
|
What makes an axon an axon?
November 10, 2008Inside every axon is a dendrite waiting to get out. Hedstrom et al. converted mature axons into dendrites by banishing a protein crucial for neuron development. The results suggest that this transformation could occur after nerve cell damage.
The study, to be published in the Nov. 17 issue of the Journal of Cell Biology, will be available online Nov. 10.
At the junction between the axon and the cell body is the axon initial segment (AIS), which sparks action potentials. Researchers also suspect that the AIS enables an axon to maintain its identity. Although scientists have teased out some of the molecular events that determine whether a neuron outgrowth will become an axon or a dendrite, they know little about what keeps these structures distinct.
In cultured neurons, Hedstrom et al. used RNAi to cut production of ankyrinG, a protein that helps spur formation of the AIS. Loss of ankyrinG caused the AIS to disappear. For example, sodium channels that normally crowd the AIS's plasma membrane dispersed. When ankyrinG was absent the erstwhile axons began to resemble dendrites, sprouting spines and developing excitatory synapses. Characteristic molecules from the cell body and dendrites, such as the microtubule polymerizing protein MAP2, also infiltrated the axons.
The AIS appears to serve as a filter that screens out dendritic proteins, Hedstrom et al. conclude. How the structure bars some proteins from the axon is still uncertain. Injuries and diseases can transform dendrites into axons. The findings raise the possibility that these insults could cause the reverse transformation by changing the amount of ankyrinG and altering the AIS.
Rockefeller University Press
In cultured neurons, Hedstrom et al. used RNAi to cut production of ankyrinG, a protein that helps spur formation of the AIS. Loss of ankyrinG caused the AIS to disappear. For example, sodium channels that normally crowd the AIS's plasma membrane dispersed. When ankyrinG was absent the erstwhile axons began to resemble dendrites, sprouting spines and developing excitatory synapses. Characteristic molecules from the cell body and dendrites, such as the microtubule polymerizing protein MAP2, also infiltrated the axons.
The AIS appears to serve as a filter that screens out dendritic proteins, Hedstrom et al. conclude. How the structure bars some proteins from the axon is still uncertain. Injuries and diseases can transform dendrites into axons. The findings raise the possibility that these insults could cause the reverse transformation by changing the amount of ankyrinG and altering the AIS.
Rockefeller University Press
Science News and Science Current Events Tag Cloud
This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size.
Sleep-disordered Breathing Carbon Footprint Cosmic Dust Language Development Social Behavior Chronic Obstructive Pulmonary Disease Diabetes Plate Tectonics Malpractice Volcanic Eruption Water Purification Drought Space Telescope Reflux Disease Lung Disease Corticosteroids Ear Infections Colon Cancer Genetic Mutation Pheromones Brain Disease Antioxidants Protons Hydrogen Storage Solar System
See More: Science News Tags
Axon Current Events and Axon News RSSHuntington's disease deciphered
Researchers at the University of Illinois at Chicago College of Medicine have discovered how the mutated huntingtin gene acts on the nervous system to create the devastation of Huntington's disease.
Protein regulates movement of mitochondria in brain cells
Scientists have identified a protein in the brain that plays a key role in the function of mitochondria - the part of the cell that supplies energy, supports cellular activity, and potentially wards off threats from disease.
Identification of a key molecular pathway required for brain neural circuit formation
The research group of Dr. Frédéric Charron, a researcher at the Institut de recherches cliniques de Montréal (IRCM), has made a discovery which could help treat spinal cord injuries and neurodegenerative diseases.
Mechanism of Alzheimer's suggests combination therapy needed
Researchers at the University of Illinois at Chicago College of Medicine have discovered a mode of action for mysterious but diagnostic protein snarls found in the brains of Alzheimer's patients that suggests a one-two punch of therapy may be needed to combat the neurodegenerative disease.
Turn back, wayward axon
To a growing axon, the protein RGMa is a "Wrong Way" sign, alerting it to head in another direction. As Hata et al. demonstrate in the March 9, 2009 issue of the Journal of Cell Biology, translating that signal into cellular action requires teamwork from two receptors.
Spun-sugar fibers spawn sweet technique for nerve repair
Researchers at Purdue University have developed a technique using spun-sugar filaments to create a scaffold of tiny synthetic tubes that might serve as conduits to regenerate nerves severed in accidents or blood vessels damaged by disease.
Researchers Disprove 15-year-old Theory about the Nervous System
A delay in traffic may cause a headache, but a delay in the nervous system can cause much more. University of Missouri researchers have uncovered clues identifying which proteins are involved in the development of the nervous system and found that the proteins previously thought to play a significant role, in fact, do not.
Evolution and epilepsy
Studies at the University of Pennsylvania School of Medicine on brain electrical signaling offer a fresh perspective on vertebrate evolution, provide additional evidence supporting Darwinian views of evolution, and may also lead to more effective treatment of epileptic seizures in infants.
Maintaining the brain's wiring in aging and disease
Researchers at the Babraham Institute near Cambridge, supported by the Alzheimer's Research Trust and the Biotechnology and Biological Sciences Research Council (BBSRC), have discovered that the brain's circuitry survives longer than previously thought in diseases of ageing such as Alzheimer's disease.
Claudin 11 stops the leaks in neuronal myelin sheaths
Devaux and Gow demonstrate how a tight junction protein called claudin 11 makes the neuronal myelin sheath a snug fit.
More Axon Current Events and Axon News Articles
 |
Terratec AXON AX 50 USB Guitar to MIDI Controller by Terratec The AXON AX 50 USB has arrived: It is the "little brother" of the extremely successful AXON AX 100 MKII one of the most powerful devices of its kind. The AXON AX 50 USB is based on the same technology as its "big brother," but it has additional options, such as a USB port with four additional virtual MIDI ports, which makes it ideal for state-of-the-art, computer-based recording studios.With its 32-bit RISC processor, the guitar to MIDI controller immediately translates the vibrations from each guitar string that you strike or strum and sends information about the pitch, dynamics and tone duration to the connected MIDI sound generator. The MIDI sound generator brings your music to life using any sound you choose. You want a flute accompaniment with your guitar? How about creating fat... |
 |
The Axon: Structure, Function and Pathophysiology by Stephen G. Waxman (Editor), Jeffery D. Kocsis (Editor), Peter K. Stys (Editor) Enhanced with superb illustrations, this comprehensive and up-to-date compendium includes chapters on the structure, function, and pathophysiology of axons in both the PNS and CNS. |
 |
LEGO BIONICLE® Axonn by LEGO A mighty and mysterious figure, Axonn helps the Matoran in their resistance against the evil Piraka. His giant axe slices through even the hardest rock as if it were butter. Virtually invulnerable and able to make lava balls with his bare hands. |
 |
Terratec AXON AX 100 MK II Guitar to MIDI Controller by Terratec MIDI and guitar - two different worlds until now. With the Terratec AXON AX 100 MKII Controller, the technical problems involved in connecting electric or acoustic guitars and basses to the MIDIfied recording studio world are finally a thing of the past.The ultra-fast guitar-to-MIDI controller in a single-unit rack mount has an early-recognition system that evaluates the impulses from the strings as soon as they are picked and converts them into values for pitch, dynamics and length. A 32-bit RISC processor makes it possible, opening up a whole new world of music to the guitarist.Never again will you have to change guitars to produce a different sound - just switch the MIDI channel. On the AXON AX 100 MKII guitar to MIDI controller, you can either choose from over 500 internal sounds, 10... |
 |
Guidance Cues in the Developing Brain by Springer Many complex molecular interactions are involved in the development of the mammalian brain. Molecules serving as guidance cues for migratory cells, growing axons and for recognition of postsynaptic targets are a major topic for research because they are directly involved in the formation of neuronal circuits, thus creating the foundation for subsequent functional refinement through interactions with the environment. In addition, most guidance cue molecules are also involved in plasticity, damage repair and regeneration in the adult brain. This volume reviews current knowledge on major classes of molecules involved in: guidance of growing axons; tau proteins involved in the establishment of axonal polarity, outgrowth and contact recognition; gangliosides and lectins involved in... |
 |
From Axons to Identity: Neurological Explorations of the Nature of the Self (Norton Series on Interpersonal Neurobiology) by Todd E. Feinberg (Author) A leading neuroscientist offers an intriguing scientific journey to understanding the neurobiology of the self. What can dementia, delusions, and other neurological disorders teach us about how the brain creates personal identity and a unified sense of self? Here, a leading neurobiologist offers an intriguing scientific approach to understanding the neurobiology of the self. Drawing on both the latest neuroscientific research, as well as the author's decades of experience with neurological patients, From Axons to Identity examines the link between brain and identity in fascinating new ways. Dr. Feinberg presents case studies of individuals with brain pathologies and unusual psychiatric syndromes that cause them to deny parts of their bodies or believe in the presence of... |
 |
The Ballad of John Axon by Ewan MacColl With Charles Parker & Peggy Seeger |
 |
John Axon Was A Railway Man... by Topic |
 |
Under the Greenwood Tree Starring: Keeley Hawes, James Murray, Terry Mortimer, Richard Leaf, Tony Haygarth Directed By: Nicholas Laughland Also With: Douglas Rae (Producer), Jeremy Gwilt (Producer), Kit Williams (Producer), Matthew Arlidge (Producer), Robert Bernstein (Producer), Ashley Pharoah (Writer), Thomas Hardy (Writer) In a small village in the south of England, Dick Dewy, a handsome working man, falls in love with Fancy Day, a newly arrived schoolteacher from a wealthy family who happens to be the village beauty. But other, richer men also want to win the hand of Fancy. There's Farmer Shiner, a wealthy landowner, and Reverend Maybold, the decent young vicar. Who will win Fancy's hand? And even if she agrees to marry Dick, will her father consent to the marriage? This charming, timeless story of rural life gave Thomas Hardy his first real taste of success, and with its rustic setting and moving tale of young love, it weaves a spell that still entrances today. |
 |
LEGO BIONICLE® Brutaka by LEGO Former guardian of the sacred Temple of Life who has now joined forces with the Piraka. Brutaka uses his giant rotating blade to cut through any obstacles in his obsessive search for the Mask of Life. |
| © 2009 BrightSurf.com |