The planar cell polarity (PCP) pathway, a beta-catenin-independent branch of the Writ signaling pathway, orients cells and their appendages with respect to the body axes. Diversin, the mammalian homolog of the Drosophila PCP protein Diego, acts as a molecular switch that blocks beta-catenin-dependent and promotes beta-catenin-independent Writ signaling. We report now that Diversin, containing several nuclear localization signals, translocates to the nucleus, where it interacts with the transcription factor AF9. Both Diversin and AF9 block canonical Wilt signaling; however, this occurs independently of each other, and does not require nuclear Diversin. In contrast, AF9 strongly augments the Diversin-driven activation of c-Jun N-terminal kinase (JNK)-dependent gene expression in the nucleus, and this augmentation largely depends on the presence of nuclear Diversin. Thus, our findings reveal that components of the PCP cascade translocate to the nucleus to participate in transcriptional regulation and PCP signaling. (C) 2009 Elsevier Inc. All rights reserved.