TRAF6 and neoplasm: Considering facts that TGFBR1 directly recruits TRAF637, that TAB2 mediates TAK1-TRAF6 interaction 38 and our observation that there exists a complex of TGFBR1/TRAF6/TAB2/TAK1 in lung cancer cells and 293T cells (Figures 3C-F & Figure S4A-E), our data argue the following working model for CLU's tumor suppressive role in NSCLC cells: CLU binds TGFBR1 and competes against TRAF6 for binding TGFBR1.