title: Tid1 is a new regulator of p53 mitochondrial translocation and apoptosis in cancer.
abstract: The p53 tumor suppressor protein induces apoptosis in response to genotoxic and environmental stresses. Recent studies have revealed the existence of a transcription-independent mitochondrial p53 apoptotic pathway; however, the mechanism that regulates its translocation to the mitochondria has been unknown. In this study, we show that the tumor suppressor Tid1 forms a complex with p53 under hypoxic conditions that directs p53 translocation to the mitochondria and the subsequent initiation of the mitochondrial apoptosis pathway. Loss of Tid1 expression abrogated p53 translocation to the mitochondria and inhibited apoptosis, whereas the over-expression of Tid1 promoted p53 mitochondrial localization and apoptosis. Tid1's mitochondrial signal sequence and DnaJ domain were both required for the movement of the p53-Tid1 complex from the cytosol to the mitochondria. When Tid is over-expressed in cancer cell lines expressing mutant p53 isoforms defective in transcriptional activity, mitochondrial localization and pro-apoptotic activities of the mutant p53 proteins was restored. Our results establish Tid1 as a novel regulator of p53-mediated apoptosis, and suggest that therapies designed to enhance Tid1's function in promoting mitochondrial localization of p53 and apoptosis could be an effective therapy in many cancers.
authors: Department of Biochemistry, University of Calgary, Calgary, Alberta, Canada.
authors: B Y
authors: BY
authors: Ahn
authors: D L N
authors: DL
authors: Trinh
authors: L D
authors: LD
authors: Zajchowski
authors: B
authors: B
authors: Lee
authors: A N
authors: AN
authors: Elwi
authors: S-W
authors: SW
authors: Kim
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D003600:Cytosol / Q000737:chemistry; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D016158:Genes, p53 / Q000502:physiology; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology*; D021381:Protein Transport / Q000187:drug effects* / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000502:physiology*
chemical_list: C120664:DNAJA3 protein, human; D050956:HSP40 Heat-Shock Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53