Fig. 5. Rac induces recruitment of NDP kinase to ruffles. Cells transfected with HA-tagged RacG12V (a,b,c) or RacT17N (d,e,f) were serum starved. Cells expressing RacG12V were fixed directly, whereas those expressing T17N Rac were first treated with EGF for 2 minutes. Samples were double labeled for the HA tag (a,d) and NDP kinase (b,e) with Ab-1. (c,f) Phase contrast images. In the cell that expresses activated Rac (a), NDP kinase is visible at the edge of the lamellipodium (b, arrow) and around vesicles (b, arrowheads). Expression of T17N Rac (d) inhibits accumulation of NDP kinase in ruffles in response to EGF (e; compare the transfected cell on the left with those on top right) but does not affect vesicular NDP kinase (e, arrowhead). Scale bar, 20 µm.