Fas-associated Factor 1 is a Scaffold Protein That Promotes β-transducin Repeat-containing Protein (β-TrCP)-mediated β-catenin Ubiquitination and Degradation
Overview
Affiliations
FAS-associated factor 1 (FAF1) antagonizes Wnt signaling by stimulating β-catenin degradation. However, the molecular mechanism underlying this effect is unknown. Here, we demonstrate that the E3 ubiquitin ligase β-transducin repeat-containing protein (β-TrCP) is required for FAF1 to suppress Wnt signaling and that FAF1 specifically associates with the SCF (Skp1-Cul1-F-box protein)-β-TrCP complex. Depletion of β-TrCP reduced FAF1-mediated β-catenin polyubiquitination and impaired FAF1 in antagonizing Wnt/β-catenin signaling. FAF1 was shown to act as a scaffold for β-catenin and β-TrCP and thereby to potentiate β-TrCP-mediated β-catenin ubiquitination and degradation. Data mining revealed that FAF1 expression is statistically down-regulated in human breast carcinoma compared with normal breast tissue. Consistent with this, FAF1 expression is higher in epithelial-like MCF7 than mesenchymal-like MDA-MB-231 human breast cancer cells. Depletion of FAF1 in MCF7 cells resulted in increased β-catenin accumulation and signaling. Importantly, FAF1 knockdown promoted a decrease in epithelial E-cadherin and an increase in mesenchymal vimentin expression, indicative for an epithelial to mesenchymal transition. Moreover, ectopic FAF1 expression reduces breast cancer cell migration in vitro and invasion/metastasis in vivo. Thus, our studies strengthen a tumor-suppressive function for FAF1.
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Yang E, Fan X, Ye H, Sun X, Ji Q, Ding Q J Transl Med. 2024; 22(1):157.
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Shen H, Xu J, Zhang W, Chen Q, Zhu Z, Mao Y NPJ Precis Oncol. 2024; 8(1):22.
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