title: Homo-oligomerization is the essential function of the tandem BRCT domains in the checkpoint protein Crb2.
abstract: BRCT (BRCA1 C terminus) domains are frequently found as a tandem repeat in proteins involved in DNA damage responses, such as Saccharomyces cerevisiae Rad9, human 53BP1 and BRCA1. Tandem BRCT domains mediate protein-protein and protein-DNA interactions. However, the functional significance of these interactions is largely unknown. Here we report the oligomerization of Schizosaccharomyces pombe checkpoint protein Crb2 through its tandem BRCT domains. Truncated Crb2 without BRCT domains is defective in DNA damage checkpoint signaling. However, addition of either of two heterologous dimerization motifs largely restores the functions of truncated Crb2 without BRCT domains. Replacement of Crb2 BRCT domains with a dimerization motif also renders cells resistant to the dominant negative effect of overexpressing Crb2 BRCT domains. These results demonstrate that the crucial function of the tandem BRCT domains is to oligomerize Crb2.
authors.affiliation: Departments of Molecular Biology and Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Li-Lin
authors.initials: LL
authors.lastname: Du
authors.forename: Bettina A
authors.initials: BA
authors.lastname: Moser
authors.forename: Paul
authors.initials: P
authors.lastname: Russell
mesh_terms: D020816:Amino Acid Motifs; D018797:Cell Cycle Proteins / Q000737:chemistry*; D004249:DNA Damage; D019281:Dimerization; D004307:Dose-Response Relationship, Radiation; D005838:Genotype; D005982:Glutathione Transferase / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry*; D020798:Two-Hybrid System Techniques; D014466:Ultraviolet Rays
chemical_list: D018797:Cell Cycle Proteins; C109867:Crb2 protein, S pombe; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; D005982:Glutathione Transferase