title: Analysis of mutations that dissociate G(2) and essential S phase functions of human ataxia telangiectasia-mutated and Rad3-related (ATR) protein kinase.
abstract: ATR (ataxia telangiectasia-mutated and Rad3-related) contains 16 conserved candidate autophosphorylation sites that match its preferred S/TQ consensus. To determine whether any is functionally important, we mutated the 16 candidate residues to alanine in a single cDNA to create a 16A-ATR mutant. The 16A-ATR mutant maintains kinase and G(2) checkpoint activities. However, it fails to rescue the essential function of ATR in maintaining cell viability and fails to promote replication recovery from a transient exposure to replication stress. Further analysis identified T1566A/T1578A/T1589A (3A-ATR) as critical mutations causing this separation of function activity. Secondary structure predictions indicate that these residues occur in a region between ATR HEAT repeats 31R and 32R that aligns with regions of ATM and DNA-PK containing regulatory autophosphorylation sites. Although this region is important for ATR function, the 3A-ATR residues do not appear to be sites of autophosphorylation. Nevertheless, our analysis identifies an important regulatory region of ATR that is shared among the PI3K-related protein kinase family. Furthermore, our data indicate that the essential function of ATR for cell viability is linked to its function in promoting proper replication in the context of replication stress and is independent of G(2) checkpoint activity.
authors: Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors: Edward A
authors: EA
authors: Nam
authors: Runxiang
authors: R
authors: Zhao
authors: David
authors: D
authors: Cortez
mesh_terms: D019943:Amino Acid Substitution; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016195:G2 Phase / Q000502:physiology*; D006801:Humans; D020125:Mutation, Missense; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D016196:S Phase / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases