title: Activation of protein kinase Tel1 through recognition of protein-bound DNA ends.
abstract: Double-strand breaks (DSBs) in chromosomal DNA elicit a rapid signaling response through the ATM protein kinase. ATM corresponds to Tel1 in budding yeast. Here we show that the catalytic activity of Tel1 is altered by protein binding at DNA ends via the Mre11-Rad50-Xrs2 (MRX) complex. Like ATM, Tel1 is activated through interaction with the MRX complex and DNA ends. In vivo, Tel1 activation is enhanced in sae2Δ or mre11-3 mutants after camptothecin treatment; both of these mutants are defective in the removal of topoisomerase I from DNA. In contrast, an sae2Δ mutation does not stimulate Tel1 activation after expression of the EcoRI endonuclease, which generates "clean" DNA ends. In an in vitro system, tethering of Fab fragments to DNA ends inhibits MRX-mediated DNA end processing but enhances Tel1 activation. The mre11-3 mutation abolishes DNA end-processing activity but does not affect the ability to enhance Tel1 activation. These results support a model in which MRX controls Tel1 activation by recognizing protein-bound DNA ends.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ 07101, USA.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Fukunaga
authors.forename: Youngho
authors.initials: Y
authors.lastname: Kwon
authors.forename: Patrick
authors.initials: P
authors.lastname: Sung
authors.forename: Katsunori
authors.initials: K
authors.lastname: Sugimoto
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D002166:Camptothecin / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics; D053903:DNA Breaks, Double-Stranded; D004264:DNA Topoisomerases, Type I / Q000235:genetics / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010692:Phleomycins / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D006657:Histones; D007140:Immunoglobulin Fab Fragments; D047908:Intracellular Signaling Peptides and Proteins; D010692:Phleomycins; C086930:RAD50 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025521:Tumor Suppressor Proteins; C086929:XRS2 protein, S cerevisiae; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin