title: Reduced kinase activity of polo kinase Cdc5 affects chromosome stability and DNA damage response in S. cerevisiae.
abstract: Polo-like kinases (PLKs) control several aspects of eukaryotic cell division and DNA damage response. Remarkably, PLKs are overexpressed in several types of cancer, being therefore a marker of bad prognosis. As such, specific PLK kinase activity inhibitors are already used in clinical trials and the regulation of PLK activation is a relevant topic of cancer research. Phosphorylation of threonine residues in the T-loop of the kinase domain is pivotal for PLKs activation. Here, we show that T238A substitution in the T-loop reduces the kinase activity of Cdc5, the only PLK in Saccharomyces cerevisiae, with minor effect on cell growth in unperturbed conditions. However, the cdc5-T238A cells have increased rate of chromosome loss and gross chromosomal rearrangements, indicating altered genome stability. Moreover, the T238A mutation affects timely localization of Cdc5 to the spindle pole bodies and blocks cell cycle restart after one irreparable double-strand break. In cells responding to alkylating agent metylmethane sulfonate (MMS), the cdc5-T238A mutation reduces the phosphorylation of Mus81-Mms4 resolvase and exacerbates the MMS sensitivity of sgs1Δ cells that accumulate Holliday junctions. Of importance, the previously described checkpoint adaptation defective allele, cdc5-ad does not show reduced kinase activity, defective Mms4 phosphorylation and genetic interaction with sgs1Δ. Our data define the importance of regulating Cdc5 activity through T-loop phosphorylation to preserve genome integrity and respond to DNA damage.
authors: a Department of Biosciences , University of Milan , Milano , Italy.
authors: Chetan C
authors: CC
authors: Rawal
authors: a Department of Biosciences , University of Milan , Milano , Italy.
authors: Sara
authors: S
authors: Riccardo
authors: a Department of Biosciences , University of Milan , Milano , Italy.|b Department of Pathophysiology & Transplantation , Universitá degli Studi di Milano , Milan , Italy.|c Division of Pathology , Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico , Milan , Italy.
authors: Chiara
authors: C
authors: Pesenti
authors: a Department of Biosciences , University of Milan , Milano , Italy.
authors: Matteo
authors: M
authors: Ferrari
authors: a Department of Biosciences , University of Milan , Milano , Italy.
authors: Federica
authors: F
authors: Marini
authors: a Department of Biosciences , University of Milan , Milano , Italy.
authors: Achille
authors: A
authors: Pellicioli
mesh_terms: D000256:Adenoviridae / Q000378:metabolism; D000595:Amino Acid Sequence; D059447:Cell Cycle Checkpoints / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D043171:Chromosomal Instability; D015825:Chromosomes, Fungal / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004260:DNA Repair; D015321:Gene Rearrangement; D042822:Genomic Instability; D050296:Microbial Viability; D008954:Models, Biological; D050505:Mutant Proteins / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D064047:Spindle Poles / Q000378:metabolism; D016615:Telomere / Q000378:metabolism; D013912:Threonine / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D050505:Mutant Proteins; D029701:Saccharomyces cerevisiae Proteins; D013912:Threonine; D017346:Protein Serine-Threonine Kinases; C081927:CDC5 protein, S cerevisiae
keywords: Budding yeast; DNA damage; checkpoint adaptation; genome instability; polo kinase/Cdc5