Dss1 Regulates Association of Brh2 with Rad51.

TitleDss1 Regulates Association of Brh2 with Rad51.
Publication TypeJournal Article
Year of Publication2017
AuthorsZhou Q, Holloman WK
Date Published2017 07 05
KeywordsAmino Acid Motifs, Binding Sites, Carrier Proteins, DNA, Single-Stranded, Electrophoretic Mobility Shift Assay, Enzyme Stability, Exoribonucleases, Fungal Proteins, Kinetics, Models, Molecular, Peptide Fragments, Protein Folding, Protein Interaction Domains and Motifs, Protein Interaction Mapping, Protein Multimerization, Protein Stability, Rad51 Recombinase, Recombinant Fusion Proteins, Solubility, Ustilago

Brh2, the BRCA2 ortholog in the fungus Ustilago maydis, mediates delivery of Rad51 to DNA during the course of homology-directed DNA repair. Rad51 interacts with Brh2 through the highly conserved BRC element and through a second region termed CRE located at the extreme carboxy terminus. Dss1, a small intrinsically unstructured protein that interacts with Brh2, is crucial for its activity in DNA repair, but the mechanism of this regulation is uncertain. In previous studies, we found that interaction of Brh2 with DNA was strongly modulated by association with Dss1. Here we report that CRE influences interaction of Dss1 with Brh2 and that Dss1 status markedly alters interaction of Brh2 with Rad51. While it appears that a single Rad51 protomer associates with Brh2 in complex with Dss1, loss of Dss1 is accompanied by a large increase in the number of Rad51 protomers that can associate with Brh2. Concomitant with this buildup of Rad51, Brh2 loses its ability to bind DNA. These observations suggest a feedback circuit in which release of Dss1 from Brh2 as it binds DNA triggers nucleation of a short Rad51 oligomer on Brh2, which in turn promotes dissociation of Brh2 from the DNA.

Alternate JournalBiochemistry
PubMed ID28616972
PubMed Central IDPMC5705077
Grant ListR01 GM079859 / GM / NIGMS NIH HHS / United States

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