TRAF6 and prostate cancer: We identified previously that c-Jun, a member of AP-1 transcription factors, is activated by TGF-β in a TRAF6-dependent manner leading to invasion of prostate cancer cells (Thakur et al., 2014) and that the Smad7-APC complex links TβRI to the microtubule system to promote migratory responses of prostate cancer cells (Ekman et al., 2012).