Cohesin phosphorylation and mobility of SMC1 at ionizing radiation-induced DNA double-strand breaks in human cells.
Cohesin, a hetero-tetrameric complex of SMC1, SMC3, Rad21 and Scc3, associates with chromatin after mitosis and holds sister chromatids together following DNA replication. Following DNA damage, cohesin accumulates at and promotes the repair of DNA double-strand breaks. In addition, phosphorylation of the SMC1/3 subunits contributes to DNA damage-induced cell cycle checkpoint regulation. The aim of this study was to determine the regulation and consequences of SMC1/3 phosphorylation as part of the cohesin complex. We show here that the ATM-dependent phosphorylation of SMC1 and SMC3 is mediated by H2AX, 53BP1 and MDC1. Depletion of RAD21 abolishes these phosphorylations, indicating that only the fully assembled complex is phosphorylated. Comparison of wild type SMC1 and SMC1S966A in fluorescence recovery after photo-bleaching experiments shows that phosphorylation of SMC1 is required for an increased mobility after DNA damage in G2-phase cells, suggesting that ATM-dependent phosphorylation facilitates mobilization of the cohesin complex after DNA damage.
CRUK/MRC Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Headington, Oxford OX3 7DQ, UK. christina.bauerschmidt@rob.ox.ac.uk
Christina
C
Bauerschmidt
Michael
M
Woodcock
David L
DL
Stevens
Mark A
MA
Hill
Kai
K
Rothkamm
Thomas
T
Helleday
D018797:Cell Cycle Proteins / Q000378:metabolism*; D011508:Chondroitin Sulfate Proteoglycans; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D004260:DNA Repair; D016195:G2 Phase; D006801:Humans; D046912:Multiprotein Complexes / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D011839:Radiation, Ionizing; D000097722:Cohesins; D000098550:Structural Maintenance of Chromosome Protein 1
D018797:Cell Cycle Proteins; D011508:Chondroitin Sulfate Proteoglycans; D002868:Chromosomal Proteins, Non-Histone; D046912:Multiprotein Complexes; D000097722:Cohesins; D000098550:Structural Maintenance of Chromosome Protein 1; C492318:SMC3 protein, human