Xenbase Image ID: 77480

Fig 3. Smad4 adapts to a step in ligand concentration, and Smad4 nuclear localization coincides with transcription. (A) Constructs used in generating the Smad4 cell line. Notation is as in Fig. 1A. (B) Snapshots from a time-lapse movie of cells exposed to 5 ng/mL TGF-β1 at time t = 0. Smad4 is enriched in the nucleus after 1 h but becomes mostly cytoplasmic by 4 h. (C) Quantification of single-cell trajectories (colored lines) and average trajectory (black line). (D) Comparison of average RFP-Smad2 and GFP-Smad4 fluorescence in the nucleus as a function of the duration of continuous TGF-β1 treatment. Smad2 nuclear accumulation is sustained, whereas Smad4 is transient. (E) Smad4 amplitude but not kinetics is dependent on the dose of TGF-β1 ligand. Comparison of average nuclear to cytoplasmic GFP-Smad4 in cells treated with either 0.1 or 5 ng/mL TGF-β1. (F) Smad4 kinetics does not require continuous signaling. C2C12 GFP-Smad4 Cells were treated with 5 ng/mL TGF-β1 only or with 5 ng/mL TGF-β1 and then with 10 μM SB431542 1 h later. Traces show average nuclear fluorescence as a function of time. Image published in: Warmflash A et al. (2012) Copyright © 2012. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View

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