Biology 2382B Lecture Notes - Lecture 13: Microvillus, Filamin, Myosin
19 Apr 2016
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Document Summary
Atp-bound actin subunits add faster at the plus-end than at the minus-end of an actin filament, resulting in a lower critical concentration and treadmilling at steady state. The rate of addition of atp-g- actin is much faster at the plus-end than at the minus-end, whereas the rate of dissociation of adp-g- actin is similar at the two ends. This difference results in a lower critical concentration at the plus-end (0. 12 m). At steady state, atp-actin is added preferentially at the plus-end, giving rise to a short region of the filament containing atp-actin and regions containing adp-pi-actin and adp-actin toward the minus-end. At steady state, atp-g-actin subunits add preferentially to the plus-end, while adp-g-actin subunits disassemble from the minus-end, giving rise to a treadmilling of subunits. The critical concentration of the minus-end of actin is 0. 60 m. Treadmilling can also be achieved in tubulin/microtubules, but most often the minus-end is capped and removal cannot occur.
