Table 2.
Op18 promotes microtubule plus end catastrophes at pH 7.5
| 11 μM Tb | 11 μM Tb + 1.7 μM Op18 | 11 μM Tb + 2.7 μM Op18 | |
|---|---|---|---|
| Plus ends | |||
| Ve (μm/min) ± SD | 2.04 ± 0.34 | 1.97 ± 0.30 | 1.79 ± 0.61 |
| n | 61 | 64 | 22 |
| Time obs (min) | 141 | 116.6 | 19.8 |
| Vre (μm/min) ± SD | 62.4 ± 28.4 | 55.9 ± 23.9 | 41.4 ± 7.2 |
| n | 16 | 35 | 19 |
| Time obs (min) | 4.35 | 9.3 | 2.86 |
| Kcat (s−1) ± SD | 0.0019 ± 0.0005 | 0.0049 ± 0.0008 | 0.013 ± 0.003 |
| n | 16 | 34 | 16 |
| Range | 0.0011–0.0031 | 0.0034–0.0068 | 0.0074–0.021 |
| Kres (s−1) ± SD | 0.0077 ± 0.005 | 0.0018 ± ND | NO |
| n | 2 | 1 | 0 |
| Minus ends | |||
| Ve (μm/min) ± SD | 0.66 ± 0.26 | 0.67 ± 0.27 | 0.71 ± 0.26 |
| n | 54 | 42 | 12 |
| Time obs (min) | 94.4 | 52.8 | 17 |
| Vre (μm/min) ± SD | 42.3 ± 31.3 | 33.2 ± 27.8 | 38.5 ± 14.7 |
| n | 36 | 28 | 7 |
| Time obs (min) | 5 | 4 | 1.1 |
| Kcat (s−1) ± SD | 0.0064 ± 0.001 | 0.0088 ± 0.002 | 0.0068 ± 0.003 |
| n | 36 | 28 | 7 |
| Range | 0.0045–0.0089 | 0.0059–0.013 | 0.0027–0.014 |
| Kres (s−1) ± SD | 0.04 ± 0.01 | 0.038 ± 0.01 | NO |
| n | 12 | 9 | 0 |
Parameters of dynamic instability measured in Buffer D as described in MATERIALS AND METHODS. Ve, Elongation rate; Vrs, shortening rate; Kcat, catastrophe frequency; Kres, rescue frequency; n, number of events; Time obs, total time observed; NO, not observed; ND, not determined; Range, lower and upper limits of the mean at 95% confidence calculated assuming a Poisson distribution of growth times (Johnson and Kotz, 1969).