CDK1 Phosphorylation of YAP Promotes Mitotic Defects and Cell Motility and Is Essential for Neoplastic Transformation

Abstract

The Yes-associated protein YAP is a downstream effector of the Hippo pathway of cell cycle control which plays important roles in tumorigenesis. Hippo-mediated phosphorylation YAP, mainly at S127, inactivates YAP function. In this study, we define a mechanism for positive regulation of YAP activity that is critical for its oncogenic function. Specifically, we found that YAP is phosphorylated in vitro and in vivo by the cell cycle kinase CDK1 at T119, S289, and S367 during G2/M phase of the cell cycle. We also found that ectopic expression of a phosphomimetic YAP mutant (YAP3D, harboring T119D/S289D/S367D) was sufficient to induce mitotic defects in immortalized epithelial cells, including centrosome amplification, multipolar spindles and chromosome missegregation. Finally, we documented that mitotic phosphorylation of YAP was sufficient to promote cell migration and invasion in a manner essential for neoplastic cell transformation. In support of our findings, CDK1 inhibitors largely suppressed cell motility mediated by activated YAP-S127A but not the phosphomimetic mutant YAP3D. Collectively, our results reveal a previously unrecognized mechanism for controlling the activity of YAP that is crucial for its oncogenic function mediated by mitotic dysregulation.

Phosphorylation of Tyr188 in the WW domain of YAP1 plays an essential role in YAP1-induced cellular transformation

“…27 Last, the CDK1 phosphorylates YAP at T119, S128, S138, S289 and S367, which promotes mitotic defects and decreases YAP mediated anti-apoptosis potential induced by the anti-tubulin drugs. 28,29 In the present study, we confirmed most of these post-translational modifications in YAP (Fig. 1) and more interestingly, identified a novel Y188 phosphorylation site and showed that its phosphorylation played a critical role in the regulation of YAP oncogenic functions.…”

“…As shown in Figure 1, we confirmed 4 potential serine phosphorylation sites in YAP1 by Lats1/2 at 61, 109, 127 and 164; 25,26 4 potential phosphorylation sites by JNKs at T119, S138, T154 and S317; 27 and 5 potential phosphorylation sites at T119, S128, S138, S289 and S367 by CDK1. 28,29 More importantly, we identified several additional serine/threonine phosphorylation sites (Fig. 1).…”

Oncoprotein YAP Regulates the Spindle Checkpoint Activation in a Mitotic Phosphorylation-dependent Manner through Up-regulation of BubR1

“…Retroviral wild type YAP and YAP mutant constructs have been described (23). Myc-CDC14A/B expression constructs were provided by Dr. Jiri Lukas and have been described (24).…”

“…The siRNA-resistant YAP cDNA (siR-YAP) and YAP phosphorylation-deficient mutants were cloned into the Tet-All retroviral vector, which contains both reverse tetracycline-controlled transactivator and tetracycline response element promoter (23). Doxycycline-inducible HeLa cells were generated by retrovirus infection and resistance selection (23).…”

“…We have recently discovered that mitotic phosphorylation of YAP by CDK1 is essential for YAP-driven oncogenic transformation, cell migration, and invasion (23). Furthermore, hypermitotic phosphorylation of YAP promoted mitotic defects in immortalized epithelial cells.…”