Lee, JihyeAdelmant, GuillaumeMarto, JarrodLee, Dong-Hyun2015-10-012015Lee, Jihye, Guillaume Adelmant, Jarrod A. Marto, and Dong-Hyun Lee. 2015. “Dephosphorylation of DBC1 by Protein Phosphatase 4 Is Important for p53-Mediated Cellular Functions.” Molecules and Cells 38 (8): 697-704. doi:10.14348/molcells.2015.0066. http://dx.doi.org/10.14348/molcells.2015.0066.1016-8478http://nrs.harvard.edu/urn-3:HUL.InstRepos:22857022Deleted in breast cancer-1 (DBC1) contributes to the regulation of cell survival and apoptosis. Recent studies demonstrated that DBC is phosphorylated at Thr454 by ATM/ATR kinases in response to DNA damage, which is a critical event for p53 activation and apoptosis. However, how DBC1 phosphorylation is regulated has not been studied. Here we show that protein phosphatase 4 (PP4) dephosphorylates DBC1, regulating its role in DNA damage response. PP4R2, a regulatory subunit of PP4, mediates the interaction between DBC1 and PP4C, a catalytic subunit. PP4C efficiently dephosphorylates pThr454 on DBC1 in vitro, and the depletion of PP4C/PP4R2 in cells alters the kinetics of DBC1 phosphorylation and p53 activation, and increases apoptosis in response to DNA damage, which are compatible with the expression of the phosphomimetic DBC-1 mutant (T454E). These suggest that the PP4-mediated dephosphorylation of DBC1 is necessary for efficient damage responses in cells.en-USdeleted in breast cancer-1dephosphorylationDNA damage responseprotein phosphatase 4Journal Article2015-10-0110.14348/molcells.2015.0066