TPX2 Inhibits Eg5 by Interactions with both Motor and Microtubule

摘要: Abstract The microtubule-associated protein, TPX2, regulates the activity of mitotic kinesin, Eg5, but mechanism regulation is not established. Using total internal reflection fluorescence (TIRF) microscopy, we observed that in extracts mammalian cells expressing Eg5-EGFP, moved processively toward microtubule plus-end at an average velocity 14 nm/s. TPX2 bound to microtubules with apparent dissociation constant ~ 200 nM and binding was dependent on C-terminal tails tubulin. single molecule assays, found full-length dramatically reduced Eg5 whereas truncated which lacks domain required for interaction a less effective inhibitor same concentration. To determine region(s) are performed microtubule-gliding assays. Dimeric, monomeric, differentially inhibited by demonstrating dimerization, or residues neck region, important Eg5. These results show both contribute motor inhibition demonstrate utility cell biophysical