THAP1 is a nuclear proapoptotic factor that links prostate-apoptosis-response-4 (Par-4) to PML nuclear bodies.
Promyelocytic leukemia (PML) nuclear bodies (PML NBs) are discrete subnuclear domains organized by the promyelocytic leukemia protein PML, a tumor suppressor essential for multiple apoptotic pathways. We have recently described a novel family of cellular factors, the THAP proteins, characterized by the presence at their amino-terminus of an evolutionary conserved putative DNA-binding motif, designated THAP domain. Here, we report that THAP1 is a novel nuclear proapoptotic factor associated with PML NBs, which potentiates both serum withdrawal- and TNF alpha-induced apoptosis, and interacts with prostate-apoptosis-response-4 (Par-4), a well characterized proapoptotic factor, previously linked to prostate cancer and neurodegenerative diseases. We show that endogenous Par-4 colocalizes with ectopic THAP1 within PML NBs in primary endothelial cells and fibroblasts. In addition, we found that Par-4 is a component of PML NBs in blood vessels, a major site of PML expression in vivo. Finally, we investigated the role of the THAP domain in THAP1 activities and found that this putative DNA-binding domain is not required for Par-4 binding and localization within PML NBs, but is essential for THAP1 proapoptotic activity. Together, our results provide an unexpected link between a nuclear factor of the THAP family, the proapoptotic protein Par-4 and PML nuclear bodies.
Roussigne
Myriam
M
Laboratoire de Biologie Vasculaire, Institut de Pharmacologie et de Biologie Structurale, CNRS UMR 5089, 205 route de Narbonne, 31077 Toulouse, France.
Cayrol
Corinne
C
Clouaire
Thomas
T
Amalric
François
F
Girard
Jean-Philippe
JP
D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D000071156:Promyelocytic Leukemia Protein; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; C474080:THAP1 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C101296:prostate apoptosis response-4 protein; C070576:PML protein, human