The p53-inducible TSAP6 gene product regulates apoptosis and the cell cycle and interacts with Nix and the Myt1 kinase.
The p53 tumor suppressor protein plays a crucial role in tumorigenesis 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 G(2)/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.
Passer
Brent J
BJ
Molecular Engines Laboratories, 20 Rue Bouvier, 75011 Paris, France.
Nancy-Portebois
Vanessa
V
Amzallag
Nathalie
N
Prieur
Sylvie
S
Cans
Christophe
C
Roborel de Climens
Aude
A
Fiucci
Giusy
G
Bouvard
Veronique
V
Tuynder
Marcel
M
Susini
Laurent
L
Morchoisne
Stéphanie
S
Crible
Virginie
V
Lespagnol
Alexandra
A
Dausset
Jean
J
Oren
Moshe
M
Amson
Robert
R
Telerman
Adam
A
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D005434:Flow Cytometry; D016193:G1 Phase; D016195:G2 Phase; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D051379:Mice; D008938:Mitosis; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D015513:Oncogene Proteins; D010088:Oxidoreductases; D010766:Phosphorylation; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016196:S Phase; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques
C116838:BNIP3L protein, human; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D010088:Oxidoreductases; C486677:STEAP3 protein, human; C473329:TSAP6 protein, mouse; D008156:Luciferases; D005982:Glutathione Transferase; C490680:Myt1 kinase, rat; D011505:Protein-Tyrosine Kinases; C490679:PKMYT1 protein, human; D017346:Protein Serine-Threonine Kinases