BI236 Lecture Notes - Lecture 9: Miosis, Tubulin, Microtubule
Document Summary
Highway for vesicle traf cking: axonemal microtubules. Model for microtubules assembly in vitro: tubulin dimers aggregate intodigomeus > nucleation, oligomers form linear chains called proto laments, proto laments associated to form sheets, sheets with 13 proto laments can close into tube, enolgation via addiction of tubular heterodimers. Monitored by observing the amount of light scattered by a solution containing gtp-tubulin after it warmed from 0-37 degrees celsius. Elongation phase > mts grow rapidly causing the concentration of tubule subunits in the solution to decline. Plateau phase > when the concentration of tubular subunits is low enough to limit further assembly, the plates phase is reached, during which subunits are added and removed from. Gtp hydrolysis and dynamic instability of mts: growth gtp-tubulin added, catastrophe: gtp hydrolyzed mt depolymerizes rapidly, rescue: growth resumes. The concentration of tubulin bound to gtp is crucial to the dynamic instability model. Gtp-tubulin is high > a large gtp cap.
