How does axon guidance work?
Axon guidance molecules can be subdivided into attractive and repulsive cues that act either over long distances or locally, in a contact-dependent manner. Cooperation between long- and short-range guidance cues is required for the navigation of growing axons to their target cells.
What signaling events are responsible for attraction of growth cones?
Activation of DCC (or TRK receptors for BDNF) leads to the release of calcium from intracellular stores through IP3 receptors, which in turn activates plasma membrane TRP channels and voltage‐dependent calcium channels (VDCC). The resulting gradient of intracellular calcium directs growth cone attraction.
What mechanism is necessary for growth cone motility?
The dynamics of actin filament polymerization, depolymerization and linkage to other components of the P-domain are responsible for many aspects of growth cone motility. However, the production of mechanical forces within this actin system is another important component.
What is axon guidance and growth cone?
Organization of cytoskeletal components (actin filaments and microtubules) in the growth cone. Growth cones facilitate axon growth and guidance by bundling and extending actin filaments into structures known as filopodia and microspikes.
What are axons do?
axon, also called nerve fibre, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. Most axons of vertebrates are enclosed in a myelin sheath, which increases the speed of impulse transmission; some large axons may transmit impulses at speeds up to 90 metres (300 feet) per second.
Why are guidepost cells important to the process of axon guidance?
Guidepost cells are populations of neurons or glia that express guidance cues at different stages of white matter tract formation. They enable step-by-step navigation of the brain environment, facilitating the guidance of axons across long distances.
What is an axon process?
An axon is a long process of a neuron (or nerve cell) involved in the conduction of nerve impulse away from the cell body. Each nerve cell has one axon, which can be over a foot long. A nerve cell communicates with another nerve cell by transmitting signals from the branches at the end of its axon.
What happens when axon is damaged?
If an axon is damaged along its way to another cell, the damaged part of the axon will die (Figure 1, right), while the neuron itself may survive with a stump for an arm. The problem is neurons in the central nervous system have a hard time regrowing axons from stumps.
What do guidepost cells do?