Fig. 4. Inhibition of dynein activity blocks process formation induced by acidic calponin. Panel A shows a cell that overexpresses ac.CaP-RFP and extends several processes. Panel B shows that a cell overexpressing dynamitin-GFP does not display any morphological change. The Red color corresponds to cells expressing ac.CaP-RFP, the green color indicates cells overexpressing dynamitin-GFP. Panel C corresponds to the overlay of panels A and B. Panels D-F illustrate the same cells double transfected with ac.CaP-RFP (in red) and dynamitin-GFP (in green). Panel F corresponds to the overlay of panels D and E. It shows that all cells overexpressing both ac.CaP-RFP and dynamitin-GFP do not develop processes. Note also that cells double transfected with ac.CaP-RFP and dynamitin-GFP are smaller than cells expressing either ac.CaP-RFP (A) or dynamitin-GFP (B). Bar, 30 µm.