Activating Transcription Factor 2 (ATF2) is a member of the ATF/CREB bZIP family of transcription factors and an oncogene in prostate cancer. ATF2 has been reported to be a critical substrate of the CUL3-SPOP-RBX1 E3 ubiquitin ligase complex and the recurrent somatic mutation of SPOP has been believed to be a key feature of prostate cancer. However, the deubiquitinating enzyme required for ATF2 stabilization is still unknown. Here, we show that ATF2 is associated with ubiquitin-specific protease 14 (USP14), which increased the protein abundance and transcriptional activity of ATF2. Pharmacologic inhibition or siRNA-mediated depletion of USP14 resulted in the decline and inactivation of ATF2. USP14 deubiquitinates and activates ATF2, resulting in enhanced prostate cancer cells proliferation both in vitro and in vivo. Importantly, silencing of ATF2 largely attuned USP14-mediated prostate cancer cells proliferation. Thus, our data revealed a critical role of USP1-ATF2 axis in the progress of prostate cancer and the inhibition of USP14 might be a promising strategy against prostate cancer. (C) 2020 Elsevier Inc. All rights reserved.