The p53-Inducible TSAP6 Gene Product Regulates Apoptosis and the Cell Cycle and Interacts with Nix and the Myt1 Kinase

• Published in: Proceedings of the National Academy of Sciences - PNAS 2003-03, Vol.100 (5), p.2284-2289
• Main Authors: Passer, Brent J., Nancy-Portebois, Vanessa, Amzallag, Nathalie, Prieur, Sylvie, Cans, Christophe, de Climens, Aude Roborel, Fiucci, Giusy, Bouvard, Véronique, Tuynder, Marcel, Susini, Laurent, Morchoisne, Stéphanie, Crible, Virginie, Lespagnol, Alexandra, Dausset, Jean, Oren, Moshe, Amson, Robert, Telerman, Adam
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies; Apoptosis; Biological Sciences; Blotting, Northern; Blotting, Western; Cancer; Cell Cycle; Cell Cycle Proteins; Cell lines; Cell nucleus; Cells; Cellular Biology; Cellular immunity; Cloning; Cloning, Molecular; DNA, Complementary - metabolism; Flow Cytometry; G1 Phase; G2 Phase; Genetics; Glutathione Transferase - metabolism; HeLa Cells; Humans; K562 cells; Life Sciences; Luciferases - metabolism; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane Proteins - physiology; Mice; Mitosis; Molecular Sequence Data; Neurotransmitters; Oligonucleotides, Antisense - pharmacology; Oncogene Proteins; Oxidoreductases; Phosphorylation; Precipitin Tests; Promoter Regions, Genetic; Protein Binding; Protein Biosynthesis; Protein Serine-Threonine Kinases - metabolism; Protein Structure, Tertiary; Protein-Tyrosine Kinases - metabolism; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2 - metabolism; Recombinant Fusion Proteins - metabolism; RNA, Messenger - metabolism; RNA, Small Interfering - metabolism; S Phase; Sequence Homology, Amino Acid; Small interfering RNA; Time Factors; Transcription, Genetic; Tumor Cells, Cultured; Tumor Suppressor Protein p53 - metabolism; Tumor Suppressor Proteins; Two-Hybrid System Techniques; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0530298100

The p53 tumor suppressor protein plays a crucial role in tumori-genesis by controlling cell-cycle progression and apoptosis. We have previously described a transcript designated tumor suppressor activated pathway-6 (TSAP6) that is up-regulated in the p53-inducible cell line, LTR6. Cloning of the murine and human full-length TSAP6 cDNA revealed that it encodes a 488-aa protein with five to six transmembrane domains. This gene is the murine and human homologue of the recently published rat pHyde. Antibodies raised against murine and human TSAP6 recognize a 50- to 55-kDa band induced by p53. Analysis of the TSAP6 promoter identified a functional p53-responsive element. Functional studies demonstrated that TSAP6 antisense cDNA diminished levels of the 50- to 55-kDa protein and decreased significantly the levels of p53-induced apoptosis. Furthermore, TSAP6 small interfering RNA inhibited apoptosis in TSAP6-overexpressing cells. Yeast two-hybrid analysis followed by GST/in vitro-transcribed/translated pull-down assays and in vivo coimmunoprecipitations revealed that TSAP6 associated with Nix, a proapoptotic Bcl-2-related protein and the Myt1 kinase, a negative regulator of the G2/M transition. Moreover, TSAP6 enhanced the susceptibility of cells to apoptosis and cooperated with Nix to exacerbate this effect. Cell-cycle studies indicated that TSAP6 could augment Myt1 activity. Overall, these data suggest that TSAP6 may act downstream to p53 to interface apoptosis and cell-cycle progression.