title: Beta-lapachone activates a Mre11p-Tel1p G1/S checkpoint in budding yeast.
abstract: Beta-lapachone is an anticancer agent that selectively induces cell death in several human cancer cells. The mechanism of beta-lapachone cytotoxicity is not yet fully understood. Here we report that beta-lapachone treatment delayed cell cycle progression at the G(1)/S transition, incremented phosphorylation of the Rad53p checkpoint kinase and decreased cell survival in the budding yeast Saccharomyces cerevisiae. Furthermore, beta-lapachone induced phosphorylation of histone H2A at serine 129. These checkpoint responses were regulated by Mec1p and Tel1p kinases. Mec1p was required for Rad53p/histone H2A phosphorylation and cell survival following beta-lapachone treatment in asynchronous cultures, but not for the G(1) delay. The tel1Delta mutation increased sensitivity to beta-lapachone in a mec1 defective strain and compromised checkpoint responses in G(1). Both Rad53p phosphorylation and G(1) delay were fully dependent on a functional Mre11p-Rad50p Xrs2p (XMR) complex, and mutants in the XMR complex were hypersensitive to beta-lapachone treatment. Finally, XRS2 and TEL1 worked epistatically regarding beta-lapachone sensitivity and Xrs2p was phosphorylated in a Tel1p-dependent manner after beta-lapachone treatment. Taken together, these findings indicate that beta-lapachone activates a Mre11p-Tel1p checkpoint pathway in budding yeast. Given the conserved nature of the Mre11p-Tel1p pathway, these results suggest that activation of the Mre11-Tel1p checkpoint could be of significance for beta-lapachone anti-tumour activity.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia, Valencia, Spain.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Menacho-Márquez
authors.forename: José R
authors.initials: JR
authors.lastname: Murguía
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D002453:Cell Cycle; D017124:Conserved Sequence; D004706:Endodeoxyribonucleases / Q000378:metabolism / Q000502:physiology*; D005090:Exodeoxyribonucleases / Q000378:metabolism / Q000502:physiology*; D016193:G1 Phase; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D009154:Mutation; D009285:Naphthoquinones / Q000494:pharmacology*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology*; D004718:Saccharomycetales; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
chemical_list: D000890:Anti-Infective Agents; D047908:Intracellular Signaling Peptides and Proteins; D009285:Naphthoquinones; D029701:Saccharomyces cerevisiae Proteins; D016159:Tumor Suppressor Protein p53; C014638:beta-lapachone; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae