ANAT 262 Lecture Notes - Lecture 11: Ndc80, Profilin, Coiled Coil
30 Aug 2016
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Document Summary
Kinetochore on surface of condensed chromatids, multiple mts at surface of plate. At kinetochore: many coiled-coil ndc80 binds weakly to sides of mts. As mt depolarizes: net force pulling back, transient dissociation of ndc80 off mt to allow depolymerization, reattach further down mt, velcro . Contractility: pull on features of cell relative to each other, pull on features relative to env"t. Treadmilling: adding subunits from one end, subtracting from other. Tuning one parameter can greatly accelerate on/off rate. Nucleus: fixed oligomer size beyond which there is rapid polymer growth, middle b/w where disassembly & assembly favoured. * = high affinity site, new subunits can make 2 contacts. Arp2/3 complex forms high affinity corner addition site, act as artificial nucleus. Complex usually binds to existing actin filament first new branch, 70 degrees. 2 c-shaped monomers; one half detaches from end allowing insertion of another action monomer binds to new monomer.
