Boundaries and physical characterization of a new domain shared between mammalian 53BP1 and yeast Rad9 checkpoint proteins.
Eukaryotic cells have evolved DNA damage checkpoints in response to genome damage. They delay the cell cycle and activate repair mechanisms. The kinases at the heart of these pathways and the accessory proteins, which localize to DNA lesions and regulate kinase activation, are conserved from yeast to mammals. For Saccharomyces cerevisiae Rad9, a key adaptor protein in DNA damage checkpoint pathways, no clear human ortholog has yet been described in mammals. Rad9, however, shares localized homology with both human BRCA1 and 53BP1 since they all contain tandem C-terminal BRCT (BRCA1 C-terminal) motifs. 53BP1 is also a key mediator in DNA damage signaling required for cell cycle arrest, which has just been reported to possess a tandem Tudor repeat upstream of the BRCT motifs. Here we show that the major globular domain upstream of yeast Rad9 BRCT domains is structurally extremely similar to the Tudor domains recently resolved for 53BP1 and SMN. By expressing several fragments encompassing the Tudor-related motif and characterizing them using various physical methods, we isolated the independently folded unit for yeast Rad9. As in 53BP1, the domain corresponds to the SMN Tudor motif plus the contiguous HCA predicted structure region at the C terminus. These domains may help to further elucidate the structural and functional features of these two proteins and improve knowledge of the proteins involved in DNA damage.
Service de Biochimie Post-Génomique et Toxicologie Nucléaire, Direction des Sciences du Vivant (DSV)--Département d'Ingénierie et d'Etudes des Protéines (DIEP), Commissariat à l'Energie Atomique (CEA-VALRHO), Bagnols-sur-Céze, France.
Béatrice
B
Alpha-Bazin
Alain
A
Lorphelin
Nathalie
N
Nozerand
Gaëlle
G
Charier
Charles
C
Marchetti
Frédéric
F
Bérenguer
Joël
J
Couprie
Bernard
B
Gilquin
Sophie
S
Zinn-Justin
Eric
E
Quéméneur
D000595:Amino Acid Sequence; D019313:BRCA1 Protein / Q000737:chemistry* / Q000502:physiology; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism; D004249:DNA Damage; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D016159:Tumor Suppressor Protein p53; D000071857:Tumor Suppressor p53-Binding Protein 1
D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; C498301:TP53BP1 protein, human; D016159:Tumor Suppressor Protein p53; D000071857:Tumor Suppressor p53-Binding Protein 1; C069930:rad9 protein