Concentration of myosin IIA at the cell periphery and in contact with the DMS in WT megakaryocytes. (A) Sections of WT mouse femora stained with anti–myosin IIA followed by goat anti–rabbit AF488 antibodies were examined by confocal microscopy. Myosin is present throughout the cytoplasm with a high concentration at the cell periphery. Bar represents 5 μm. (B) Saponin-permeabilized megakaryocytes were incubated with an anti–myosin IIA antibody followed by 10 nm gold-conjugated protein A. After epon embedding, sections were cut and examined by TEM. Myosin IIA is organized in thick filaments at the base of the peripheral zone (PZ) (▲). m indicates mitochondria; α, alpha granule. Bar represents 200 nm. (C) Immunogold labeling of sections of Lowicryl-embedded megakaryocytes. Myosin IIA is in contact with the DMS (). Bar represents 200 nm.