p73alpha regulation by Chk1 in response to DNA damage.
The checkpoint kinase 1 (Chk1) is an essential component of the DNA damage checkpoint. Previous studies have demonstrated an indispensable role for the p53-related transcription factor p73alpha in DNA damage-induced apoptosis. Here, we provide evidence that p73alpha is a target of Chk1. We found that endogenous p73alpha is serine phosphorylated by endogenous Chk1 upon DNA damage, which is a mechanism required for the apoptotic-inducing function of p73alpha. Consistent with this, we discovered that endogenous p73alpha interacts with Chk1 and is phosphorylated by Chk1 at serine 47 in vitro and in vivo. In contrast, Chk2 does not phosphorylate p73alpha in vitro. Moreover, mutation of serine 47 abolishes both Chk1-dependent phosphorylation of p73alpha upon DNA damage in vivo and the ability of Chk1 to upregulate the transactivation capacity of p73alpha. Our data indicate a novel biochemical pathway through which the p73alpha proapoptotic function requires DNA damage-triggered p73alpha phosphorylation by Chk1.
Division of Molecular Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Susana
S
Gonzalez
Carol
C
Prives
Carlos
C
Cordon-Cardo
D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016147:Genes, Tumor Suppressor; D006801:Humans; D066298:In Vitro Techniques; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D015533:Transcriptional Activation; D014162:Transfection; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D012694:Serine; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1