Table I.

MT dynamics parameters quantified upon expression of different constructs

Growth rate, vgaShortening rate, vsaCatastrophe frequency, kcatbRescue frequency, kresb
μm min−1μm min−1s−1s−1
Control:
 EGFP21.5 ± 8.2
 65 MTs35.6 ± 12.8
 403 MTs0.003 ± 0.002
 65 MTs0.17 ± 0.03
 403 MTs
Dominant negative:
 EGFP–CLIP-170 Δhead21.8 ± 13.0
 76 MTs33.7 ± 19.0
 76 MTs0.005 ± 0.006
 76 MTs0.024 ± 0.005
 400 MTs
Rescue experiment I:
 EBFP–CLIP-170 Δhead + EGFP–CLIP-170 head19.6 ± 11.7
 91 MTs33.6 ± 13.6
 400 MTs0.003 ± 0.002
 91 MTs0.16 ± 0.03
 400 MTs
Rescue experiment II:
 EBFP–CLIP-170 Δhead + EGFP-p150Glued head19.0 ± 6.9
 71 MTs30.0 ± 9.4
 350 MTs0.004 ± 0.003
 71 MTs0.05 ± 0.016
 350 MTs
  • a Growth and shortening rates and SDs were calculated from frequency histograms of instantaneous rates.

  • b Catastrophe and rescue frequencies were calculated from MT life histories for each cell as the number of transition events over integrated time of observation of individual phases; numbers given are average and SD for the population of cells. Number of transition events and integrated times were as follows: control, 12 catastrophes for 2,337 s and 385 rescues for 2,248 s; dominant negative, 9 catastrophes for 1,328 s and 141 rescues for 6,096 s; rescue experiment I, 8 catastrophes for 2,604 s and 397 rescues for 2,556 s; rescue experiment II, 11 catastrophes for 3,156 s and 254 rescues for 5,558 s.