Table 2.

Parameters of dynamic instability for cytoplasmic microtubules in vivo.

Tubulin form	Tub2-BBBBB	Tub2-YYYYY
Polymerization Rate (μm/min)	1.4 ± 0.7 (30)	1.7 ± 0.7 (33)
Depolymerization Rate (μm/min)	1.9 ± 0.7 (38)*	2.6 ± 1.2 (38)
Catastrophe Frequency (per min)	0.59 (28)	0.64 (29)
Rescue Frequency (per min)	1.07 (21)	1.33 (25)
Time spent polymerizing, %	24	29
Time spent depolymerizing, %	29	29
Time spent attenuated, %	46	42
polymerization duration, s	33 ± 13 (30)	34 ± 16 (33)
depolymerization duration, s	31 ± 15 (38)	30 ± 15 (33)
attenuation duration, s	44 ± 28 (44)*	34 ± 16 (49)
total microtubules observed	28	28
total time observed, s	4014	3858

Number of events is in parentheses. Rates/durations are presented as mean ± SD.

^*p < 0.05 compared to Tub2-YYYYY by unpaired, two-tailed t-test.