TY - JOUR
T1 - Dynamics of Rad9 Chromatin Binding and Checkpoint Function Are Mediated by Its Dimerization and Are Cell Cycle-Regulated by CDK1 Activity
AU - Granata, Magda
AU - Lazzaro, Federico
AU - Novarina, Daniele
AU - Panigada, Davide
AU - Puddu, Fabio
AU - Abreu, Carla Manuela
AU - Kumar, Ramesh
AU - Grenon, Muriel
AU - Lowndes, Noel F.
AU - Plevani, Paolo
AU - Muzi-Falconi, Marco
PY - 2010/8/5
Y1 - 2010/8/5
N2 - Saccharomyces cerevisiae Rad9 is required for an effective DNA damage response throughout the cell cycle. Assembly of Rad9 on chromatin after DNA damage is promoted by histone modifications that create docking sites for Rad9 recruitment, allowing checkpoint activation. Rad53 phosphorylation is also dependent upon BRCT-directed Rad9 oligomerization; however, the crosstalk between these molecular determinants and their functional significance are poorly understood. Here we report that, in the G1 and M phases of the cell cycle, both constitutive and DNA damage-dependent Rad9 chromatin association require its BRCT domains. In G1 cells, GST or FKBP dimerization motifs can substitute to the BRCT domains for Rad9 chromatin binding and checkpoint function. Conversely, forced Rad9 dimerization in M phase fails to promote its recruitment onto DNA, although it supports Rad9 checkpoint function. In fact, a parallel pathway, independent on histone modifications and governed by CDK1 activity, allows checkpoint activation in the absence of Rad9 chromatin binding. CDK1-dependent phosphorylation of Rad9 on Ser11 leads to specific interaction with Dpb11, allowing Rad53 activation and bypassing the requirement for the histone branch.
AB - Saccharomyces cerevisiae Rad9 is required for an effective DNA damage response throughout the cell cycle. Assembly of Rad9 on chromatin after DNA damage is promoted by histone modifications that create docking sites for Rad9 recruitment, allowing checkpoint activation. Rad53 phosphorylation is also dependent upon BRCT-directed Rad9 oligomerization; however, the crosstalk between these molecular determinants and their functional significance are poorly understood. Here we report that, in the G1 and M phases of the cell cycle, both constitutive and DNA damage-dependent Rad9 chromatin association require its BRCT domains. In G1 cells, GST or FKBP dimerization motifs can substitute to the BRCT domains for Rad9 chromatin binding and checkpoint function. Conversely, forced Rad9 dimerization in M phase fails to promote its recruitment onto DNA, although it supports Rad9 checkpoint function. In fact, a parallel pathway, independent on histone modifications and governed by CDK1 activity, allows checkpoint activation in the absence of Rad9 chromatin binding. CDK1-dependent phosphorylation of Rad9 on Ser11 leads to specific interaction with Dpb11, allowing Rad53 activation and bypassing the requirement for the histone branch.
KW - DNA-DAMAGE CHECKPOINT
KW - DOUBLE-STRAND BREAKS
KW - HISTONE H2A PHOSPHORYLATION
KW - BUDDING YEAST RAD9
KW - SACCHAROMYCES-CEREVISIAE
KW - S-PHASE
KW - BRCT DOMAIN
KW - MEC1-DEPENDENT PHOSPHORYLATION
KW - HOMOLOGOUS RECOMBINATION
KW - CHK1 ACTIVATION
U2 - 10.1371/journal.pgen.1001047
DO - 10.1371/journal.pgen.1001047
M3 - Article
SN - 1553-7390
VL - 6
JO - PLoS genetics
JF - PLoS genetics
IS - 8
M1 - 1001047
ER -