Cell cycle-specific cleavage of Scc2 regulates its cohesin deposition activity.
Sister chromatid cohesion (SCC), efficient DNA repair, and the regulation of some metazoan genes require the association of cohesins with chromosomes. Cohesins are deposited by a conserved heterodimeric loading complex composed of the Scc2 and Scc4 proteins in Saccharomyces cerevisiae, but how the Scc2/Scc4 deposition complex regulates the spatiotemporal association of cohesin with chromosomes is not understood. We examined Scc2 chromatin association during the cell division cycle and found that the affinity of Scc2 for chromatin increases biphasically during the cell cycle, increasing first transiently in late G1 phase and then again later in G2/M. Inactivation of Scc2 following DNA replication reduces cellular viability, suggesting that this post S-phase increase in Scc2 chromatin binding affinity is biologically relevant. Interestingly, high and low Scc2 chromatin binding levels correlate strongly with the presence of full-length or amino-terminally cleaved forms of Scc2, respectively, and the appearance of the cleaved Scc2 species is promoted in vitro either by treatment with specific cell cycle-staged cellular extracts or by dephosphorylation. Importantly, Scc2 cleavage eliminates Scc2-Scc4 physical interactions, and an scc2 truncation mutant that mimics in vivo Scc2 cleavage is defective for cohesin deposition. These observations suggest a previously unidentified mechanism for the spatiotemporal regulation of cohesin association with chromosomes through cell cycle regulation of Scc2 cohesin deposition activity by Scc2 dephosphorylation and cleavage.
Molecular Biology Program, andDepartment of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045.
Julie
J
Woodman
Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045.
Tyler
T
Fara
Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045.
Monika
M
Dzieciatkowska
Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045.
Michael
M
Trejo
Molecular Biology Program, andDepartment of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045.
Nancy
N
Luong
Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045.
Kirk C
KC
Hansen
Molecular Biology Program, andDepartment of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045 paul.megee@ucdenver.edu.
Paul C
PC
Megee
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D043171:Chromosomal Instability / Q000502:physiology; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation / Q000502:physiology; D005838:Genotype; D008969:Molecular Sequence Data; D010766:Phosphorylation / Q000502:physiology; D011817:Rabbits; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D029701:Saccharomyces cerevisiae Proteins; D000097722:Cohesins; C410592:SCC2 protein, S cerevisiae; C410593:SCC4 protein, S cerevisiae
MAU2; NIPBL; Scc2 phosphorylation; chromosome instability; chromosome segregation