Figure 4.

ERM protein redistribution in response to an electric field. Osteoblasts are shown in the upper row, and hMSCs in the lower row. Immunofluorescently labeled ezrin, radixin, and moesin proteins were uniformly distributed across the osteoblast membrane, likely due to high density ERM binding sites on the dense actin meshwork contiguous to the membrane (A). In contrast, in normal hMSCs ERM linkers were found localized only along the stress fibers adjacent to the juxtaposed membrane (D). After cell stimulation with a 2 V/cm field for 60 min, the amount of active (phosphorylated membrane-bound) ERM proteins seemed to decrease in osteoblast (B) as well as in hMSC (E). Similar effect was achieved by ATP depletion using 10 mM sodium azide and 10 mM 2-deoxyglucose in osteoblasts (C) and hMSCs (F). All images are 100 × 100 μm in size.