The taccalonolides and paclitaxel cause distinct effects on microtubule dynamics and aster formation

Table 1 Phosphocellulose purified bovine brain microtubules were assembled to steady state in the presence of taccalonolide AJ, paclitaxel or vehicle and the dynamic instability parameters were determined

	Vehicle	1 μM AJ		3 μM AJ		250 nM PTX
	Value ± SEM	Value ± SEM	% Change	Value ± SEM	% Change	Value ± SEM	% Change
Growth rate (μm/min)	2.7 ± 0.2	3.1 ± 0.2	+15	3 ± 0.3	+11	2.8 ± 0.2	+4
Shortening rate (μm/min)	11.9 ± 1	7.4 ± 0.6^**	−38	4 ± 0.5^***	−66	5.8 ± 0.4^***	−51
Percent time growing	56	34	−39	26	−54	26	−54
Percent time shortening	19	15	−21	12	−37	22	+16
Percent time attenuated	25	51	+104	62	+148	52	+108
Catastrophe frequency (per min)	0.28 ± 0.05	0.21 ± 0.04^*	−25	0.13 ± 0.03^***	−54	0.26 ± 0.04	−7
Rescue frequency (per min)	0.84 ± 0.17	0.60 ± 0.15	−29	0.47 ± 0.15^*	−44	0.30 ± 0.09^**	−64
Dynamicity (μm/min)	2.73	1.74	−36	0.95	−65	1.63	−40

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