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Bio-317 - lecture #22, new version [Compatibility Mode]

Bio-317 - lecture #22, new version [Compatibility Mode] -...

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11/22/2011 1 The Signaling Events of Axon Guidance Maya Shelly E.mail: [email protected] Office Location: Room 530, Life Science Bldg. Office Hours: Tuesday, 12:30 PM - 1:30 PM, November, 2011 Target to innervate Axon Guidance or Pathfinding * Process by which neurons send axons to reach and innervate correct targets – a very precise process where the axons follow very precise paths in the nervous system to reach the correct target. + + + + Molecular Cues Intermediate Axon + + + + + + + + + + + + + + + + - - - - Gradients of Positive and Negative Molecular Cues Intermediate target target + + + + + + + + + - - - - - - - - - - - - - - - -
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11/22/2011 2 * Growing axons have a highly motile structure at the growing tip - Growth Cone . Growth Cone Turning in Axon Guidance * Growing axons have a highly motile structure at the growing tip - Growth Cone . * The growth cone reacts to the extracellular environment : The extracellular environment possesses molecular cues, soluble molecules Growth Cone Turning in Axon Guidance The extracellular environment possesses molecular cues, soluble molecules secreted into the environment or bound molecules (like the extracellular matrix proteins), that instruct the axon to which direction to grow and navigate. * The growth cones express on their cell-surface receptors for these external cues. * The extracellular/receptor interaction leads to activation of intracellular signaling events . * These molecular cues can be attractive to the growth cone or repulsive : and are translated into a turning response of the growth cone – chemotropic response : Attraction – turning of the growth cone towards the molecular cue, Repulsion – turning of the growth cone away from the molecular cue.
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