ANAT 262 Lecture Notes - Lecture 9: Spastin, Spindle Apparatus, Pericentriolar Material

• School: McGill University
• Department: Anatomy & Cell Biology
• Course: ANAT 262
• Professor: Ursula Stochaj

Document Summary

Individual microtubules are unsatable, stochastically switch b/w rapid growth & rapid disassembly allow microtubule explore cell. Highly coordinated & organized transition every cell cycle. Mitotic spindle that aligns dna at metaphase plate during cell division a & b tubulin are homologs, similar shape but different aa sequences & properties. Both bind gtp, catalytic activity of tubulin in b subunit, exchangeable gtp site. C-terminal tails extended & flexible: access to accessory proteins. Lateral contacts b/w protofilaments (13), a-a and b-b subunits form hollow tubes. At seam after 13 protofilaments: lateral contact a-b can have b/w 11-16 protofilaments in vitro; more wider. Straight protofilaments: ensure moving motor proteins stay on same face of microtubule. Equilibrium: total amount of polymer can assemble, still dynamic but just adding/removing at same rate. Kon function of time & concentration of free subunits, koff only function of time. In absence of gtp hydrolysis: critical concentration maintains the same at both ends; kon &