Membrane and nuclear staining of A549 Cell-Fit-HD. (a) Glucose transporter Glut1 staining visualizes the A549 cell membrane. Glut1 is mainly accumulated at the membrane. The diffuse cytoplasmic signal may arise from permeabilisation during immunofluorescent staining. (b) HOECHST staining as nuclear counterstain. (c) Merging of Glut1 and HOECHST images. A549 cells form a tightly packed monolayer with strong cell-cell adhesion. (d) A section of (a) with different color coding (blue-green-yellow) is shown. The distinct yellow bright spots indicate a discrete strong accumulation of Glut1 at the membrane. Scale bars, 20 μ m. (a)-(d) were obtained by confocal fluorescent microscopy.