Biology 2382B Lecture Notes - Dynactin, Katanin, Basal Body
20 Nov 2012
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Document Summary
7-9 nm, intermediate filaments 10 nm. Polymer of - - monomers (55 kda each). Found in dimer (110 kda each and 8nm long!) because it is more stable. Dimers form protofilaments which then form hollow tubes. - is (-) end and - is (+) = polarity! Both - - monomers can bind gtp, however only -monomer can hydrolyze the. Gtp creates stronger bonds, once hydrolyzed, easier to disassemble. Protofilaments can arrange into singlets (13 protofilaments that are relatively unstable, constantly rearranged) or doublets (13+10, found in cilia and flagella axonemel microtubules nothing to do with axons) or triplets (13+10+10, found in basal bodies and centrioles). Centrosome: is the microtubule organizing center (mtoc) in mammals. Made of centrioles which are nine triplets at 90 to each other. Note that microtubules do not arise directly from centrioles but rather from -tubulin (specifically, -turc, -tubulin ring complex provides nucleating sites) and the protein pericentrin.
