title: Prohibitin induces the transcriptional activity of p53 and is exported from the nucleus upon apoptotic signaling.
abstract: Prohibitin, a potential tumor suppressor protein, has been shown to inhibit cell proliferation and repress E2F transcriptional activity. Though prohibitin has potent transcriptional functions in the nucleus, a mitochondrial role for prohibitin has also been proposed. Here we show that prohibitin is predominantly nuclear in two breast cancer cell lines where it co-localizes with E2F1 and p53. Upon apoptotic stimulation by camptothecin, prohibitin is exported to perinuclear regions where it localizes to mitochondria. The data presented here also show that prohibitin is capable of physically interacting with p53 in vivo and in vitro. Prohibitin was found to enhance p53-mediated transcriptional activity and cotransfection of an antisense prohibitin construct reduces p53-mediated transcriptional activation. Prohibitin appears to induce p53-mediated transcription by enhancing its recruitment to promoters, as detected by chromatin immunoprecipitation assays. These results suggest that prohibitin is capable of modulating Rb/E2F as well as p53 regulatory pathways.
mesh_terms: D021581:Active Transport, Cell Nucleus; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis; D001665:Binding Sites; D015153:Blotting, Western; D002166:Camptothecin / Q000378:metabolism / Q000494:pharmacology; D018797:Cell Cycle Proteins; D002455:Cell Division; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense / Q000737:chemistry; D011233:Precipitin Tests; D000091402:Prohibitins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2; D012097:Repressor Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense; D000091402:Prohibitins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D016160:Retinoblastoma Protein; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D005982:Glutathione Transferase; D002166:Camptothecin