(A) Western blot of IQGAP1, cofilin, phospho-cofilin (p-cofilin), and p-LIMK, and quantification of p-cofilin (n = 5) and p-LIMK (n = 3) in mature MKs after thrombopoietin-induced differentiation. n = 5. (B) WT and 2B MKs after thrombopoietin-induced differentiation in culture were incubated over a fibrinogen matrix for 3 hours and stained for F-actin and total cofilin or p-cofilin (on Ser3). Scale bars: 10 μm. White squares indicate the magnification zone. Statistical significance was determined by Student’s t test. *P < 0.05, ***P < 0.001.