PICK1 and ICA69 co-localize in the Golgi compartment of COS7 cells and promote punctate distribution of GFP-tagged chromogranin A (CgA-GFP) in the cytosol.

Abstract

<p>(A) Confocal images of COS-7 cells transfected with GFP-PICK1 (top), HA-ICA69 (middle), or GFP-PICK1 and HA-ICA69 (bottom). From left, the channels show GFP-PICK1 in green, HA-ICA69 in red, and endogenous giantin in blue. Upon co-expression, GFP-PICK1 and ICA69 co-localize with giantin in the Golgi compartment. Scale bar, 10 µm. (B) Confocal images of COS-7 cells transfected with CgA-GFP and pcDNA3 (top) or together with mycPICK1 and HA-ICA69 (bottom). From left, the green channel shows CgA-GFP, the red channel shows mycPICK1, and the blue channel shows HA-ICA69. Insets illustrate the marked increase in punctuate CgA structures in cells co-transfected with mycPICK1 and HA-ICA69. Outlines of the cells are shown in the green channel in white. Scale bar, 10 µm. Images are representative of <i>n</i> = 50 (CgA-GFP) and <i>n</i> = 44 (CgA-GFP+mycPICK1+HA-ICA69) cells from three independent sessions. (C) Quantification of the punctuate CgA-GFP signal relative to the total CgA-GFP signal as a measure of the efficiency of Golgi exit. ***<i>p</i><0.001 in Student's <i>t</i> test.</p