title: TERT regulates cell survival independent of telomerase enzymatic activity.
abstract: Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, plays a pivotal role in the maintenance of telomeres and cell proliferation. Here we report that down-regulation of hTERT induces apoptosis independently of telomerase enzymatic activity in human breast cancer cells. Expression of a hTERT mutant lacking telomerase activity rescues the cells with lowered telomerase without inducing cell death. With similar patterns of subcellular distribution to that of the tumor suppressor protein p53 during mitosis, hTERT interacts with p53 and poly(ADP-ribose) polymerase (PARP). Decreasing p53 expression in intact cells worsens, and increasing p53 prevents, cell death induced by lowering hTERT. Thus, hTERT maintains cell survival and proliferation via both telomerase enzymatic activity-dependent telomere lengthening and enzymatic activity-independent intermolecular interactions involving p53 and PARP.
authors.affiliation: Molecular Signaling Laboratory, Baker Medical Research Institute, Commercial Road, Prahran, Victoria 3181, Australia.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
authors.forename: He
authors.initials: H
authors.lastname: Li
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Deb
authors.forename: Jun-Ping
authors.initials: JP
authors.lastname: Liu
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001943:Breast Neoplasms / Q000473:pathology; D002455:Cell Division; D002470:Cell Survival; D004268:DNA-Binding Proteins; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D009363:Neoplasm Proteins / Q000502:physiology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D016372:RNA, Antisense / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D019098:Telomerase / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D016615:Telomere / Q000648:ultrastructure; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000201:enzymology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D016372:RNA, Antisense; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D011065:Poly(ADP-ribose) Polymerases; C509186:TERT protein, human; D019098:Telomerase