The Hippo signaling pathway plays a critical role in body development and tissue growth. As the core effector of the Hippo signaling pathway, Yes-associated protein (YAP) has been reported to be involved in various kinds of human cancers. However, the mechanism for the regulation of YAP activity has not been completely understood. In this study, we constructed a YAP Thr425Ala mutant and found that this mutation decreased YAP transcriptional activity. Further, T425A retained YAP in the cytoplasm without affecting the phosphorylation of YAP S127. Moreover, we observed that the T425A mutation attenuated the ability of YAP in driving MCF10A cell migration. Our research indicates that T425 of YAP is important for the regulation of YAP localization and activity.