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. 2010 Jun 7;120(7):2474–2485. doi: 10.1172/JCI42150

Figure 6. ESL-1 can directly bind to TGF-β and inhibits TGF-β signaling.

Figure 6

(A) ESL-1 coimmunoprecipitates with both the proTGF-βs and TGF-β ligands. Transfection scheme is shown at the top. Note that anti-V5 antibody detects the V5-tagged proTGF-β1, proTGF-β2 (~50 kDa), and mature TGF-β peptides (TGF-β1: 15 kDa and TGF-β2: 12 kDa). The top 4 panels show Western blots of input lysates, and the bottom 3 show Western blot (WB) for immunoprecipitation. Antibodies used are listed on the left. ProTGF-β1 and proTGF-β2 and their mature ligands are all immunoprecipitated with Myc antibody, and vice versa, suggesting direct interaction between TGF-β and ESL-1. (B) ESL-1 cannot bind mature TGF-β without LAP. rhTGF-β1 (100 ng) was added to lysates of COS7 cells expressing ESL-1-Myc and then coimmunoprecipitated with anti-Myc antibody. The precipitates were analyzed with reducing Western blots. rhTGF-β1 (15 ng) was used as loading control (asterisk). (C) ESL-1 can effectively inhibit TGF-β activity from the plasmid-produced proTGF-β1 but cannot inhibit signaling from the exogenously added rhTGF-β1 (n = 3; **P < 0.01).