Fig. 4. IRAP and PIKfyve colocalise on highly dynamic vesicles. (A) A 3T3-L1 adipocyte, under basal conditions, coexpressing GFP-PIKfyve (left panel) and IRAP-mRFP1 (middle panel) was imaged by confocal microscopy. The right hand panel shows an overlay of the two images. Boxes B and C indicate two different GFP-PIKfyve and IRAP-mRFP1 coexpressing vesicles that are magnified and indicated with arrows in panels B and C, respectively. In Box D, another GFP-PIKfyve and IRAP-mRFP1 coexpressing vesicle enters the perinuclear region and exhibits behaviour suggestive of fusion with other membranous structures. For optimal viewing of this vesicle see the animation provided as supplementary material. (B,C) Sequential images of GFP-PIKfyve (upper panels) and IRAP-mRFP1 (lower panels) expression, 1 second apart were collected over two different time periods. This time-lapse sequence is best viewed in the accompanying supplementary material. Note that the IRAP-mRFP1 fluorescence has been enhanced to improve the resolution on peripheral vesicular structures; this results in the overexposure of fluorescence in the perinuclear region. Bars, 10 µm.