|Dss1 release activates DNA binding potential in Brh2.
|Year of Publication
|Zhou Q, Kojic M, Holloman WK
|2012 Nov 13
|DNA Repair, DNA-Binding Proteins, Fungal Proteins, Protein Binding, Ustilago
Dss1 is an intrinsically unstructured polypeptide that partners with the much larger Brh2 protein, the BRCA2 ortholog in Ustilago maydis, to form a tight complex. Mutants lacking Dss1 have essentially the same phenotype as mutants defective in Brh2, implying that through physical interaction Dss1 serves as a positive activator of Brh2. Dss1 associates with Brh2 through an interaction surface in the carboxy-terminal region. Certain derivatives of Brh2 lacking this interaction surface remain highly competent in DNA repair as long as a DNA-binding domain is present. However, the Dss1-independent activity raises the question of what function might be met in the native protein by having Brh2 under Dss1 control. Using a set of Brh2 fusions and truncated derivatives, we show here that Dss1 is capable of exerting control when there is a cognate Dss1-interacting surface present. We find that association of Dss1 attenuates the DNA binding potential of Brh2 and that the amino-terminal domain of Brh2 helps evict Dss1 from its carboxy-terminal interaction surface. The findings presented here add to the notion that Dss1 serves in a regulatory capacity to dictate order in association of Brh2's amino-terminal and carboxy-terminal domains with DNA.
|PubMed Central ID
|GM42482 / GM / NIGMS NIH HHS / United States
GM79859 / GM / NIGMS NIH HHS / United States
R01 GM042482 / GM / NIGMS NIH HHS / United States
R01 GM079859 / GM / NIGMS NIH HHS / United States
Submitted by mam2155 on March 24, 2014 - 4:14pm