Figure 4.

Overexpression of GFP-CPE_C25 Disrupts Transport of Secretory Vesicles Containing Fluorescence-Tagged CPE and POMC in Live Anterior Pituitary Cells

A, Tracks of each CPE-RFP vesicle movement in cells expressing GFP alone (supplemental Fig. 4 video 1). Scale bar, 5 μm. B, Tracks of each CPE-RFP vesicle movement in cells expressing GFP-CPE_C25 (supplemental Fig. 4 video 2). Scale bar, 5 μm. C, Bar graph showing the number of vesicles that moved and the duration of their movement. Note the reduction in the total number of vesicles that moved and the reduced duration of the vesicles that did move in the GFP-CPE_C25-expressing cells compared with GFP alone. D, Graphs showing analyses of live cell images of in vivo movement of CPE-RFP secretory vesicles in primary cultures of anterior pituitary cells transfected with GFP-CPE_C25, which has a similar competitive behavior as CPE_C10 (see Fig. 1D). The number of cells analyzed was 43 vesicles in two cells for GFP and 28 vesicles in 5 cells for GFP-CPE_C25 (supplemental Fig. 4 videos 1 and 2). Each image was taken at a time interval of 0.984 sec and the total distance calculated. Both the overall velocity and duration of vesicle movement were decreased by overexpression of GFP-CPE_C25.