| MDMX that is phosphorylated by UV activated Chk 1 , resulting in p 53 activation . ^^^ Here , our study shows that this inhibition can be overcome by 14 3 3gamma and Chk 1 . 14 3 3gamma was identified as an MDMX associated protein via an immuno affinity purification coupled mass spectrometry . ^^^ Interestingly , in response to UV irradiation , the wild type , but not the kinase dead mutant , Chk 1 phosphorylated MDMX at serine 367 , enhanced the 14 3 3gamma MDMX binding and the cytoplasmic retaining of MDMX . ^^^ Thus , these results demonstrate 14 3 3gamma and Chk 1 as two novel regulators of MDMX in response to UV irradiation . . ^^^ |