Dpb11 activates the Mec1–Ddc2 complex |
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| Authors: | Daniel A. Mordes Edward A. Nam David Cortez |
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| Affiliation: | Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232 |
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| Abstract: | The Saccharomyces cerevisiae Mec1–Ddc2 checkpoint kinase complex (the ortholog to human ATR-ATRIP) is an essential regulator of genomic integrity. The S. cerevisiae BRCT repeat protein Dpb11 functions in the initiation of both DNA replication and cell cycle checkpoints. Here, we report a genetic and physical interaction between Dpb11 and Mec1–Ddc2. A C-terminal domain of Dpb11 is sufficient to associate with Mec1–Ddc2 and strongly stimulates the kinase activity of Mec1 in a Ddc2-dependent manner. Furthermore, Mec1 phosphorylates Dpb11 and thereby amplifies the stimulating effect of Dpb11 on Mec1–Ddc2 kinase activity. Thus, Dpb11 is a functional ortholog of human TopBP1, and the Mec1/ATR activation mechanism is conserved from yeast to humans. |
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| Keywords: | ATR checkpoint DNA damage TopBP1 |
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