Molecular mimicry of SUMO promotes DNA repair.
Rad60 family members contain functionally enigmatic, integral SUMO-like domains (SLDs). We show here that despite their divergence from SUMO, each Rad60 SLD interacts with a subset of SUMO pathway enzymes: SLD2 specifically binds the SUMO E2 conjugating enzyme (Ubc9), whereas SLD1 binds the SUMO E1 (Fub2, also called Uba2) activating and E3 (Pli1, also called Siz1 and Siz2) specificity enzymes. The molecular basis of this selectivity is revealed by our 0.97-A resolution crystal structure of Rad60 SLD2, which shows that apart from the conserved non-substrate SUMO:Ubc9 interface, the surface features of SLD2 are distinct from those of SUMO. Abrogation of the SLD2:Ubc9 FEG motif-dependent interaction results in hypersensitivity to genotoxic stress and an increase in spontaneous recombination associated with aberrant replication forks. Our results provide a mechanistic basis for the near-synonymous roles of Rad60 and SUMO in survival of genotoxic stress and suggest unprecedented DNA-damage-response functions for SLDs in regulating sumoylation.
Prudden
John
J
Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.
Perry
J Jefferson P
JJ
Arvai
Andrew S
AS
Tainer
John A
JA
Boddy
Michael N
MN
D002470:Cell Survival; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004249:DNA Damage; D004260:DNA Repair; D042822:Genomic Instability; D018716:Molecular Mimicry; D050505:Mutant Proteins / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic / Q000235:genetics; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry* / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000737:chemistry / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D000098843:Ubiquitin-Conjugating Enzyme UBC9
D002868:Chromosomal Proteins, Non-Histone; D050505:Mutant Proteins; C455501:Rad60 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9