Changes in cytoplasmic viscosity correlate with altered mitotic kinetics. (A) Time for control and CA-WASp U937 cells to progress from NEB to anaphase when cultured with DMSO or 20μM CK666; n > 35 cells per condition over 4 independent experiments. (B) Time for U937 cells from panel A to progress from anaphase to the start of furrowing. (C) Apparent cytoplasmic viscosity and cellular elasticity in HT1080 cells. (D) Time for HT1080 cells to progress from anaphase to the start of furrowing when cultured with DMSO, 20μM or 40μM CK666; n > 33 cells per condition over 4 independent experiments. (E) Peak anaphase chromatid velocity of HT1080 cells shown in panel D. (F) Normalized anaphase chromatid velocity as a function of the inverse normalized apparent cytoplasmic viscosity in HT1080 cells. (G) Period of oscillation of prometaphase kinetochore pairs. *Significant difference (P < .01) from control; #significant difference (P < .01) from CA-WASp.