MCB 2210 Lecture Notes - Lecture 12: Gelsolin, Neuropathology, Cofilin
3 Apr 2016
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Document Summary
The role of nucleotides in mt dynamics: gtp hydrolysis accompanies microtubule assembly, during elongation, gtp-containing tubulin subunits add onto the (+) ends of mts, gtp is hydrolyzed to gdp after the tubulin subunit incorporates into the. Mt: thus, a growing (+) end of a mt will consist of a cap of gtp subunits a. However, at concentrations of unpolymerized tubulin near the cc, the rate of addition of gtp-tubulin to the end slows. This is because gtp-tubulin more readily makes lateral interactions with other protofilaments that maintain the cylindrical structure of the end. For this reason, it is called catastrophic disassembly or catastrophe: mts can also regrow. Mt can also change from growth to shrinkage (catastrophe), or from shrinkage to growth (rescue). This property of mts is called dynamic instability: the alternation between growing and shrinking states occurs randomly and is due to conversions between a gtp and gdp cap at the plus end.
