title: Regulation of intra-S phase checkpoint by ionizing radiation (IR)-dependent and IR-independent phosphorylation of SMC3.
abstract: Structure maintenance of chromosome 1 (SMC1) is phosphorylated by ataxia telangiectasia-mutated (ATM) in response to ionizing radiation (IR) to activate intra-S phase checkpoint. A role of CK2 in DNA damage response has been implicated in many previous works, but the molecular mechanism for its activation is not clear. In the present work, we report that SMC3 is phosphorylated at Ser-1067 and Ser-1083 in vivo. Ser-1083 phosphorylation is IR-inducible, depends on ATM and Nijmegen breakage syndrome 1 (NBS1), and is required for intra-S phase checkpoint. Interestingly, Ser-1067 phosphorylation is constitutive and is not induced by IR but also affects intra-S phase checkpoint. Phosphorylation of Ser-1083 is weakened in cells expressing S1067A mutant, suggesting interplay between Ser-1067 and Ser-1083 phosphorylation in DNA damage response. Consistently, small interfering RNA knockdown of CK2 leads to attenuated phosphorylation of Ser-1067 as well as intra-S phase checkpoint defect. Our data provide evidence that phosphorylation of a core cohesin subunit SMC3 by ATM plays an important role in DNA damage response and suggest that a constitutive phosphorylation by CK2 may affect intra-S phase checkpoint by modulating SMC3 phosphorylation by ATM.
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Luo
authors.forename: Yehua
authors.initials: Y
authors.lastname: Li
authors.forename: Jung-Jung
authors.initials: JJ
authors.lastname: Mu
authors.forename: Jinglan
authors.initials: J
authors.lastname: Zhang
authors.forename: Toru
authors.initials: T
authors.lastname: Tonaka
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hamamori
authors.forename: Sung Yun
authors.initials: SY
authors.lastname: Jung
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
mesh_terms: D019943:Amino Acid Substitution; D064007:Ataxia Telangiectasia Mutated Proteins; D047390:Casein Kinase II / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011508:Chondroitin Sulfate Proteoglycans / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage / Q000235:genetics / Q000528:radiation effects*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011839:Radiation, Ionizing; D016196:S Phase / Q000528:radiation effects*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D000098550:Structural Maintenance of Chromosome Protein 1
chemical_list: D018797:Cell Cycle Proteins; D011508:Chondroitin Sulfate Proteoglycans; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C112156:NBN protein, human; D009687:Nuclear Proteins; D021122:Protein Subunits; D034741:RNA, Small Interfering; C492318:SMC3 protein, human; D025521:Tumor Suppressor Proteins; D000098550:Structural Maintenance of Chromosome Protein 1; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases