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SAPK pathways and p53 cooperatively regulate PLK4 activity and centrosome integrity under stress

Nature Communications 2013 Apr 30;4:1775. doi: 10.1038/ncomms2752
Nakamura T, Saito H, Takekawa M.
[1] Division of Cell Signaling and Molecular Medicine, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan [2] Department of Cell Signaling and Molecular Medicine, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan [3] Division of Molecular Cell Signaling, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan [4] Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.

Polo-like kinase 4 is essential for centrosome duplication, but its hyperactivation causes supernumerary centrosomes. Here we report that polo-like kinase 4 is directly phosphorylated and activated by stress-activated protein kinase kinase kinases (SAPKKKs). Stress-induced polo-like kinase 4 activation promotes centrosome duplication, whereas stress-induced SAPK activation prevents centrosome duplication. In the early phase of stress response, the balance of these opposing signals prevents centrosome overduplication. However, in the late phase of stress response, p53 downregulates polo-like kinase 4 expression, thereby preventing sustained polo-like kinase 4 activity and centrosome amplification. If both p53 and the SAPKK MKK4 are simultaneously inactivated, as is frequently found in cancer cells, persistent polo-like kinase 4 activity combined with the lack of SAPK-mediated inhibition of centrosome duplication conspire to induce supernumerary centrosomes under stress. Indeed, tumour-derived MKK4 mutants induced centrosome amplification under genotoxic stress, but only in p53-negative cells. Thus, our results reveal a mechanism that preserves the numeral integrity of centrosomes, and an unexplored tumour-suppressive function of MKK4.