Tipin and Timeless form a mutually protective complex required for genotoxic stress resistance and checkpoint function.
Tipin is a mammalian protein that interacts with Timeless, which plays a role in DNA damage checkpoint responses. Here, we show that Tipin is a nuclear protein that associates with the replicative helicase and protects cells against genotoxic agents. Tipin is required for efficient cell cycle arrest in response to DNA damage, and depletion of Tipin renders cells sensitive to ionizing radiation as well as replication stress. Loss of Tipin results in spontaneous gamma-H2AX foci, a marker for DNA double-strand breaks. We find that Tipin and Timeless form a complex that maintains the level of both proteins in cells and that the loss of either one will lead to the loss of the interacting partner. This observation explains the similar checkpoint phenotypes observed in both Tipin- and Timeless-depleted cells.
Chou
Danny M
DM
Department of Genetics, Howard Hughes Medical Institute, Center for Genetics and Genomics, Brigham and Women's Hospital, Harvard University Medical School, Boston, MA 02115, USA.
Elledge
Stephen J
SJ
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004249:DNA Damage / Q000235:genetics*; D004268:DNA-Binding Proteins; D006657:Histones / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D012680:Sensitivity and Specificity
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C509769:TIMELESS protein, human; C516227:Tipin protein, human