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. Author manuscript; available in PMC: 2012 Aug 26.
Published in final edited form as: Cell Metab. 2010 Sep 8;12(3):250–259. doi: 10.1016/j.cmet.2010.08.005

Figure 1. GLUT4 structures in the vicinity of PM.

Figure 1

(A) Isolated rat adipose cells were transiently transected with HA-GLUT4-GFP and imaged using a combination of TIRF (red) and WF (green) microscopy. The overlay image shows that the majority of HA-GLUT4-GFP is present in the TIRF-zone close to PM. Bar, 5 μm.

(B) Scheme of experiment. TIRF microscopy selectively images HA-GLUT4-GFP structures localized in the TIRF-zone (within 200 nm of PM), while the WF image comprises fluorescence from PM and the full thickness of the adjacent layer of cytoplasm (thickness of ~1 μm). N - Nucleus; LD - lipid droplet.

(C) Zoomed image of a single GLUT4 punctum detected in a TIRF image. Diffraction-limited GLUT4 puncta may represent (from left to right): GSV in the vicinity of PM (tethered or untethered), a vesicle undergoing exocytosis or endocytosis, and/or GLUT4 molecules clustered in PM.

(D) Histogram of GLUT4 structure distribution in the TIRF-zone in the absence of insulin. The distance from PM (TIRF interface) was calculated for individual GLUT4 puncta from the ratio of TIRF/WF signals. Note the significant amount of GLUT4 structures localized within 100 nm of PM.