title: Mammalian TIMELESS is required for ATM-dependent CHK2 activation and G2/M checkpoint control.
abstract: Timeless (Tim), a core circadian clock gene in Drosophila, is retained in mammals but has no apparent mammalian circadian clock function. Mammalian TIM is essential for ATR-dependent Chk1 activation and S-phase arrest. We report that TIM is likewise essential for ATM-dependent Chk2-mediated signaling of doxorubicin-induced DNA double strand breaks. TIM depletion attenuates doxorubicin-induced G(2)/M cell cycle arrest and sensitizes cancer cells to doxorubicin-induced cytotoxicity. TIM is, thereby, a potential novel anticancer drug target whose inhibition may enhance the therapeutic cytotoxicity of agents that activate DNA damage pathways as part of their mechanism.
authors.affiliation: Medical Chronobiology Laboratory, Wm Jennings Bryan Dorn Veterans Affairs Medical Center, Columbia, SC 29209, USA.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yang
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Wood
authors.forename: William J M
authors.initials: WJ
authors.lastname: Hrushesky
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002455:Cell Division; D045744:Cell Line, Tumor; D064447:Checkpoint Kinase 2; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology; D016195:G2 Phase; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013997:Time Factors; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; C509769:TIMELESS protein, human; D025521:Tumor Suppressor Proteins; D004317:Doxorubicin; D064447:Checkpoint Kinase 2; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases