Mrc1 phosphorylation in response to DNA replication stress is required for Mec1 accumulation at the stalled fork.
DNA replication stress activates a response pathway that stabilizes stalled forks and promotes the completion of replication. The budding yeast Mec1 sensor kinase, Mrc1 mediator, and Rad53 effector kinase are central to this signal transduction cascade in S phase. We report that Mec1-dependent, Rad53-independent phosphorylation of Mrc1 is required to establish a positive feedback loop that stabilizes Mec1 and the replisome at stalled forks. A structure-function analysis of Mrc1 also uncovered a central region required for proper mediator function and association with replisome components. Together these results reveal new insight into how Mrc1 facilitates checkpoint signal amplification at stalled replication forks.
Naylor
Maria L
ML
Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, Boston, MA 02115, USA.
Li
Ju-mei
JM
Osborn
Alex J
AJ
Elledge
Stephen J
SJ
D018797:Cell Cycle Proteins / Q000737:chemistry / Q000502:physiology*; D064447:Checkpoint Kinase 2; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000502:physiology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000502:physiology; D016196:S Phase; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D013312:Stress, Physiological
C102209:CDC45 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C441579:MRC1 protein, S cerevisiae; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D064447:Checkpoint Kinase 2; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae