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. Author manuscript; available in PMC: 2013 Oct 2.
Published in final edited form as: Exp Cell Res. 2011 May 18;317(14):1955–1969. doi: 10.1016/j.yexcr.2011.05.009

Figure 2. STAT3 Associates with Vesicular Structures.

Figure 2

Blots shown are characteristic of results seen within at least three separate and replicate experiments. (A) Subcellular fractions isolated from IL-6 (20 ng/mL) treated HepG2 cells using Balch homogenization and differential centrifugation as described within the materials and methods section. (B) Transmission electron microscopy of the combined 16,000 x g and 115,000 x g “endosomes” fraction after phosphotungstic acid negative staining, showing and enriched population of membrane-bound organelles. (C) HepG2 cells were treated with IL-6 (20 ng/mL) for the indicated period of time and subcellular fractions were isolated. The endosomes and nuclear fractions were prepared as described and incubated with a biotinylated M67 SIE oligonucleotide to test the DNA binding capacity of STAT3 within these fractions. Protein bound to DNA was separated by pull down with neutravidin beads and identified as ‘SIE Pulldown’. Protein that did not bind DNA and precipitate with neutravidin beads is identified as ‘No Pulldown’.