Fig. 1. Localization of NDP kinase in quiescent and EGF-treated NIH-3T3 cells. (a) In resting cells, NDP kinase accumulates in ring-like structures (v) that correspond to phase-bright cytoplasmic vesicles (b). (c) In cells treated with 10 ng ml^–1 EGF for 2 minutes, NDP kinase is present in lamellipodia and ruffles (r) as well as around cytoplasmic vesicles (v); (d) the corresponding phase-contrast image. Arrowheads indicate areas where the intensity of the fluorescence signal does not coincide with phase-dark areas. NDP kinase was visualized with polyclonal Ab-1. Scale bar, 25 µm.