Differential activity of NMII isoforms. (A) Representative fluorescence recovery kinetics of NMIIA and NMIIB in CD41a⁺CD42⁺ megakaryocytes (MK) on day 7 of in vitro culture. (B) Western blot analysis of the expression of NMIIA and NMIIB in Triton X-100 fractionation-based supernatant (S) and pellet (P) fractions of in vitro cultured day 7 control megakaryocytes and megakaryocytes treated with Y27632 for 24 hours. Densitometric analysis is provided in supplemental Figure 2. (C) Representative fluorescence recovery kinetics of NMIIA-GFP and NMIIB-GFP in erythroblasts (ERY) on day 8 of culture. (D) Fluorescence recovery kinetics of NMIIA and NMIIB in CD41a⁺CD42⁺ megakaryocytes on day 7 of culture pretreated with Y27632 (ROCK inhibitor) for 24 hours. (E) Fluorescence recovery kinetics of NMIIA-GFP and NMIIB-GFP in erythroblasts on day 9 of culture after incubation in the presence of 10 μM Y27632 for 24 hours.