A, N2a cells cotransfected with APP770 V5 and GGA1 myc or empty vector were immunostained for APP (Alexa488; green), GGA1 (Cy5; blue), and the Golgi marker GM130 (Cy3; red). B, The same transfection was stained for the endosomal marker EEA1 (Cy3). C, To assess cell-surface localization, APP695 [Character 96]GFP and GGA1 [Character 96]myc or empty vector were cotransfected and then immunostained with an Ab to the APP ectodomain on ice without permeabilization (Cy3). Cells were then fixed, permeabilized, and stained for GGA1 (Cy5). (J. Neurosci. 2006 Sep 27;26(39):9913-9922)