The p53-inducible TSAP6 gene product regulates apoptosis and the cell cycle and interacts with Nix and the Myt1 kinase

Proc Natl Acad Sci U S A. 2003 Mar 4;100(5):2284-9. doi: 10.1073/pnas.0530298100. Epub 2003 Feb 26.

Abstract

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.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Apoptosis*
  • Blotting, Northern
  • Blotting, Western
  • Cell Cycle
  • Cell Cycle Proteins
  • Cloning, Molecular
  • DNA, Complementary / metabolism
  • Flow Cytometry
  • G1 Phase
  • G2 Phase
  • Glutathione Transferase / metabolism
  • HeLa Cells
  • Humans
  • Luciferases / metabolism
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism*
  • Membrane Proteins / physiology*
  • Mice
  • Mitosis
  • Molecular Sequence Data
  • 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 c-bcl-2 / metabolism
  • Proto-Oncogene Proteins*
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / metabolism
  • Recombinant Fusion Proteins / metabolism
  • S Phase
  • Sequence Homology, Amino Acid
  • Time Factors
  • Transcription, Genetic
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / metabolism*
  • Tumor Suppressor Proteins*
  • Two-Hybrid System Techniques

Substances

  • BNIP3L protein, human
  • Cell Cycle Proteins
  • DNA, Complementary
  • Membrane Proteins
  • Oligonucleotides, Antisense
  • Oncogene Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • RNA, Small Interfering
  • Recombinant Fusion Proteins
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • Oxidoreductases
  • STEAP3 protein, human
  • TSAP6 protein, mouse
  • Luciferases
  • Glutathione Transferase
  • Myt1 kinase, rat
  • Protein-Tyrosine Kinases
  • PKMYT1 protein, human
  • Protein Serine-Threonine Kinases

Associated data

  • GENBANK/AY214461
  • GENBANK/AY214462