Table 1.

Hyperactive HSPB1 mutants disturb microtubule dynamics

HSPB1WT (n = 86 MTs)HSPB1R127W (n = 103 MTs)HSPB1S135F (n = 104 MTs)
Growth (%)0.165 ± 0.1180.057 ± 0.067**0.067 ± 0.075**
Shrinkage (%)0.164 ± 0.1430.059 ± 0.063)**0.068 ± 0.068**
Pause (%)0.671 ± 0.1760.884 ± 0.097**0.865 ± 0.109**
Growth velocity (μm/s)0.257 ± 0.1280.352 ± 0.210 ns0.377 ± 0.559 ns
Shrink velocity (μm/s)0.272 ± 0.1200.349 ± 0.244**0.419 ± 0.326*
Catastrophe frequency (s−1)0.171 ± 0.1040.091 ± 0.074**0.103 ± 0.106**
Rescue frequency (s−1)0.187 ± 0.0980.087 ± 0.079**0.099 ± 0.089**

  • TUBB3-GFP MTs were imaged at 3 s intervals in HeLa cells expressing HSPB1WT, HSPB1R127W, and HSPB1S135F. Individual TUBB3-GFP MTs were tracked manually from at least 10 different cells in seven independent movies. The MT life histories are represented as the percentage of time spent in growth, shrinkage, or pause. Catastrophe frequency is given as the frequency that MTs transitioned from growth (or pause) to shrinkage. Rescue frequency corresponds to the frequency at which MTs transitioned from shrinkage (or pause) to growth. Data are presented as average ± SD.

  • ↵*p < 0.05;

  • ↵**p < 0.01. ns, Nonsignificant.