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Figure 5 | Molecular Cancer

Figure 5

From: Rac1 GTPase and the Rac1 exchange factor Tiam1 associate with Wnt-responsive promoters to enhance beta-catenin/TCF-dependent transcription in colorectal cancer cells

Figure 5

Proposed model of Rac1/Tiam1-mediated enhancement of β-catenin/TCF-4-dependent transcription. In the absence of a Wnt signal, Rac1 is tethered to TCF binding elements (TBEs) within Wnt target gene promoters along with TCF-4 and possibly other corepressors in the GDP-bound inactive state. Wnt3a stimulation promotes the formation of β-catenin/Tiam1 complexes that associate with TCF-4 and Rac1 at Wnt target gene promoters. Tiam1 activates Rac1 by mediating GDP to GTP exchange. GTP-bound active Rac1 mediates stimulatory effects on the Wnt-induced transcription factor complex to enhance Wnt target gene transcription.

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