title: Phosphorylation of Minichromosome Maintenance 3 (MCM3) by Checkpoint Kinase 1 (Chk1) Negatively Regulates DNA Replication and Checkpoint Activation.
abstract: Mechanisms controlling DNA replication and replication checkpoint are critical for the maintenance of genome stability and the prevention or treatment of human cancers. Checkpoint kinase 1 (Chk1) is a key effector protein kinase that regulates the DNA damage response and replication checkpoint. The heterohexameric minichromosome maintenance (MCM) complex is the core component of mammalian DNA helicase and has been implicated in replication checkpoint activation. Here we report that Chk1 phosphorylates the MCM3 subunit of the MCM complex at Ser-205 under normal growth conditions. Mutating the Ser-205 of MCM3 to Ala increased the length of DNA replication track and shortened the S phase duration, indicating that Ser-205 phosphorylation negatively controls normal DNA replication. Upon replicative stress treatment, the inhibitory phosphorylation of MCM3 at Ser-205 was reduced, and this reduction was accompanied with the generation of single strand DNA, the key platform for ataxia telangiectasia mutated and Rad3-related (ATR) activation. As a result, the replication checkpoint is activated. Together, these data provide significant insights into the regulation of both normal DNA replication and replication checkpoint activation through the novel phosphorylation of MCM3 by Chk1.
authors: From the Departments of Pharmacology and.
authors: Xiangzi
authors: X
authors: Han
authors: From the Departments of Pharmacology and.
authors: Franklin
authors: F
authors: Mayca Pozo
authors: Genetics and Genome Science.
authors: Jacob N
authors: JN
authors: Wisotsky
authors: Center for Proteomics and Bioinformatics, and.
authors: Benlian
authors: B
authors: Wang
authors: Division of General Medical Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106 Case Comprehensive Cancer Center.
authors: James W
authors: JW
authors: Jacobberger
authors: From the Departments of Pharmacology and Case Comprehensive Cancer Center, Genetics and Genome Science, yxz169@case.edu.
authors: Youwei
authors: Y
authors: Zhang
mesh_terms: D000409:Alanine / Q000737:chemistry; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D002453:Cell Cycle; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D002843:Chromatin / Q000737:chemistry; D004249:DNA Damage; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000235:genetics; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D013058:Mass Spectrometry; D064126:Minichromosome Maintenance Complex Component 3 / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction
chemical_list: D002843:Chromatin; D004277:DNA, Single-Stranded; C066470:MCM3 protein, human; D012694:Serine; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D064126:Minichromosome Maintenance Complex Component 3; D000409:Alanine
keywords: Cell Cycle; DNA Damage; DNA Replication; Phosphorylation; Signal Transduction