Overexpression of a kinase-inactive ATR protein causes sensitivity to DNA-damaging agents and defects in cell cycle checkpoints.
ATR, a phosphatidylinositol kinase-related protein homologous to ataxia telangiectasia mutated (ATM), is important for the survival of human cells following many forms of DNA damage. Expression of a kinase-inactive allele of ATR (ATRkd) in human fibroblasts causes increased sensitivity to ionizing radiation (IR), cis-platinum and methyl methanesulfonate, but only slight UV radiation sensitivity. ATRkd overexpression abrogates the G2/M arrest after exposure to IR, and overexpression of wild-type ATR complements the radioresistant DNA synthesis phenotype of cells lacking ATM, suggesting a potential functional overlap between these proteins. ATRkd overexpression also causes increased sensitivity to hydroxyurea that is associated with microtubule-mediated nuclear abnormalities. These observations are consistent with uncoupling of certain mitotic events from the completion of S-phase. Thus, ATR is an important component of multiple DNA damage response pathways and may be involved in the DNA replication (S/M) checkpoint.
Cliby
W A
WA
The Seattle Project, Program in Molecular Pharmacology, Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.
Roberts
C J
CJ
Cimprich
K A
KA
Stringer
C M
CM
Lamb
J R
JR
Schreiber
S L
SL
Friend
S H
SH
D064007:Ataxia Telangiectasia Mutated Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002461:Cell Line, Transformed; D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication; D005347:Fibroblasts / Q000187:drug effects / Q000528:radiation effects; D016195:G2 Phase / Q000528:radiation effects; D006801:Humans; D008938:Mitosis / Q000528:radiation effects; D010641:Phenotype; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011836:Radiation Tolerance
D018797:Cell Cycle Proteins; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases