1. Spd2 assists Spd1 in the modulation of ribonucleotide reductase architecture but does not regulate deoxynucleotide pools.
- Author
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Vejrup-Hansen R, Fleck O, Landvad K, Fahnøe U, Broendum SS, Schreurs AS, Kragelund BB, Carr AM, Holmberg C, and Nielsen O
- Subjects
- Adaptor Proteins, Signal Transducing metabolism, Allosteric Regulation genetics, Amino Acid Sequence, Cell Cycle genetics, Cell Cycle Proteins genetics, Cell Cycle Proteins isolation & purification, Checkpoint Kinase 2 metabolism, DNA Repair genetics, Intrinsically Disordered Proteins genetics, Intrinsically Disordered Proteins isolation & purification, Molecular Sequence Data, Mutation genetics, Nucleotidases metabolism, Protein Conformation, Schizosaccharomyces genetics, Schizosaccharomyces pombe Proteins genetics, Schizosaccharomyces pombe Proteins isolation & purification, Sequence Homology, Amino Acid, Cell Cycle Proteins metabolism, Intrinsically Disordered Proteins metabolism, Ribonucleotide Reductases metabolism, Schizosaccharomyces metabolism, Schizosaccharomyces pombe Proteins metabolism
- Abstract
In yeasts, small intrinsically disordered proteins (IDPs) modulate ribonucleotide reductase (RNR) activity to ensure an optimal supply of dNTPs for DNA synthesis. The Schizosaccharomyces pombe Spd1 protein can directly inhibit the large RNR subunit (R1), import the small subunit (R2) into the nucleus and induce an architectural change in the R1-R2 holocomplex. Here, we report the characterization of Spd2, a protein with sequence similarity to Spd1. We show that Spd2 is a CRL4(Cdt2)-controlled IDP that functions together with Spd1 in the DNA damage response and in modulation of RNR architecture. However, Spd2 does not regulate dNTP pools and R2 nuclear import. Furthermore, deletion of spd2 only weakly suppresses the Rad3(ATR) checkpoint dependency of CRL4(Cdt2) mutants. However, when we raised intracellular dNTP pools by inactivation of RNR feedback inhibition, deletion of spd2 could suppress the checkpoint dependency of CRL4(Cdt2) mutant cells to the same extent as deletion of spd1. Collectively, these observations suggest that Spd1 on its own regulates dNTP pools, whereas in combination with Spd2 it modulates RNR architecture and sensitizes cells to DNA damage., (© 2014. Published by The Company of Biologists Ltd.)
- Published
- 2014
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