Fig. 7. Ubiquilin colocalizes with Eps15 and Hrs, but not with epsin, and it is not found in clathrin-coated pits or in endosomes. (A) Colocalization of GFP-ubiquilin with endogenous Eps15 and Hrs but not with epsin. HeLa cells transiently transfected with the GFP-ubiquilin construct (a-f) were processed for fluorescence microscopy using the rabbit anti-Eps15 (a,b) and anti-Hrs (e,f) polyclonal antibodies, and the goat anti-epsin (c,d) polyclonal antibody. The first antibodies were revealed by Alexa-594-labelled goat anti-rabbit and donkey anti-goat immunoglobulin secondary antibodies. (a,c,e) Green fluorescence emitted by GFP. (b,d,f) Red fluorescence emitted by Alexa 594. Insets show higher magnifications of representative areas in which arrows stress GFP-ubiquilin dots. (B) Ubiquilin is found in neither CCPs nor endosomes. HeLa cells transiently transfected with the GFP/ubiquilin-encoding construct (a-c) were processed for fluorescence microscopy using the goat anti-CALM polyclonal antibody (a) and the mouse anti-CD63 monoclonal antibody (c) revealed with Alexa-594-labelled donkey anti-goat and goat anti-mouse immunoglobulins secondary antibodies, respectively. For transferrin staining (b), the GFP/ubiquilin-transfected cells were allowed to internalize Alexa-594-labelled transferrin for 30 minutes. GFP staining and Alexa-594 staining are shown in green and red, respectively.