Xenbase Image ID: 118984

Figure 5. The α-catenin–free, monomeric form of β-catenin exhibits preferential binding to TCF compared with cadherin in Wnt cells. (A) Rat1 cells were labeled to steady-state with [35S]methionine/cysteine, and a cytosolic fraction was prepared from each condition (−Wnt, +Wnt, 10 mM LiCl, 12 h) and immunoprecipitated with the designated antibodies or affinity precipitated with GST proteins. Note that immunoprecipitation of endogenous E-cadherin (from the 100,000 g membrane pellet, lanes 5, 10, and 16) and TCF (lane 11) are also shown. Non-specific bands were not seen with a GST control (not depicted). Overnight incubation with LiCl (10 mM) allows the α-catenin–free pool of β-catenin to bind cad-GST, TCF-GST, and the endogenous E-cadherin (lanes 14–16), equivalently. (B). COOH-terminal epitopes of β-catenin are masked in the α-catenin–free fraction of β-catenin. Equivalent amounts of an S100 fraction from [35S]methionine/cysteine steady-state–labeled Rat1+Wnt cells were immunoprecipitated with the following antibodies: anti–β-catenin NH2-terminal mAb (1.1.1; lane 1), anti–β-catenin COOH-terminal mAb (M5.2; lane 2), anti–α-catenin mAb (lane 4), and a nonimmune control (lane 3). (Lanes 5–7) PDZ protein, mLin7, preferentially binds to β-catenin–α-catenin dimer: metabolically labeled Rat1+Wnt lysates were affinity precipitated with (lane 5) anti–β-catenin pAb, (lane 6) control GST, and (lane 7) mLin7-GST. Image published in: Gottardi CJ and Gumbiner BM (2004) Copyright © 2004, The Rockefeller University Press. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View

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