title: The haploinsufficient tumor suppressor p18 upregulates p53 via interactions with ATM/ATR.
abstract: p18 was first identified as a factor associated with a macromolecular tRNA synthetase complex. Here we describe the mouse p18 loss-of-function phenotype and a role for p18 in the DNA damage response. Inactivation of both p18 alleles caused embryonic lethality, while heterozygous mice showed high susceptibility to spontaneous tumors. p18 was induced and translocated to the nucleus in response to DNA damage. Expression of p18 resulted in elevated p53 levels, while p18 depletion blocked p53 induction. p18 directly interacted with ATM/ATR in response to DNA damage. The activity of ATM was dependent on the level of p18, suggesting the requirement of p18 for the activation of ATM. Low p18 expression was frequently observed in different human cancer cell lines and tissues. These results suggest that p18 is a haploinsufficient tumor suppressor and a key factor for ATM/ATR-mediated p53 activation.
authors.affiliation: National Creative Research Initiatives Center for ARS Network, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Bum-Joon
authors.initials: BJ
authors.lastname: Park
authors.forename: Jin Wook
authors.initials: JW
authors.lastname: Kang
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Lee
authors.forename: So-Jung
authors.initials: SJ
authors.lastname: Choi
authors.forename: Young Kee
authors.initials: YK
authors.lastname: Shin
authors.forename: Young Ha
authors.initials: YH
authors.lastname: Ahn
authors.forename: Yun Hee
authors.initials: YH
authors.lastname: Choi
authors.forename: Dongho
authors.initials: D
authors.lastname: Choi
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Kim
mesh_terms: D000483:Alleles; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D064007:Ataxia Telangiectasia Mutated Proteins; D001483:Base Sequence; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation; D004249:DNA Damage / Q000502:physiology; D004268:DNA-Binding Proteins; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C576897:Atr protein, mouse; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases; D000604:Amino Acyl-tRNA Synthetases; C101946:p18 component, aminoacyl tRNA synthetase