Strongly decreased FRAP in proplatelets treated with cytoplasmic dynein inhibitors in platelet bioreactor. (A) Representative images of time-lapse microscopy of control MKs expressing β1-tubulin Dendra2 that were infused into the platelet bioreactor. FRAP was performed on formed proplatelets. White dashed arrow indicates flow direction. Dashed area indicates packs. Gap width is 1 to 2 μm. White arrows indicate photobleached ROI. Indicated numbers represent seconds. pre, before photobleaching. Scale bar is 20 µm. (B) Cells were preincubated with indicated agonists, and fluorescence intensity in photobleached ROI was measured. n = at least 5 per condition. P values after photobleaching: nocodazole treatment to control, not significant; EHNA treatment to control (**P < .01, *P < .05), except t = 8, 26, and 28 seconds; and Ciliobrevin D treatment to control (**P < .01, *P < .05 for all points).