BIOL 1013 Lecture Notes - Filopodia, Midbrain Tectum, Cell Adhesion Molecule
1 Feb 2013
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Development iii (axon guidance: principles of axon guidance, historical perspective: early evidence of axonal guidance cues. Cajal and harrison observe dynamic nature of axonal growth cone. Spinal cord inversion does not affect how motor axons select peripheral pathways: sequence of events: pathfinding, target selection, synapse formation and refinement. Actin: found in growth cone, undergoes treadmilling via myosin and actin polymerization; adhesive molecules and myosin mediate membrane protrusion. Microtubules: found polymerized in axon shaft, fills in voids in growth cone when actin is attached to membrane complexes in response to extracellular cues (this is the method of growth cone advance) Individual filopodia can steer entire growth cone via mechanism above. Molecular regulation of axonal guidance (see also lec 18 for list of sources of guidance cues: rho gtpases and cytoskeleton. Rho family members (cdc42, rac, rho) are gtpases that modulate actin cytoskeleton and are regulated by gefs and gaps. Cdc42 (filopodia) rac (lamellipodia) rho (stress fibers, focal adhesions)
