Multistep regulation of DNA replication by Cdk phosphorylation of HsCdc6
| Autor: | Tony Hunter, Wei Jiang, Nicholas J. Wells |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
DNA Replication
Male DNA re-replication Saccharomyces cerevisiae Proteins Molecular Sequence Data Cell Cycle Proteins Eukaryotic DNA replication Saccharomyces cerevisiae Antibodies Cell Line DNA replication factor CDT1 Replication factor C Control of chromosome duplication Schizosaccharomyces Humans Nuclear Matrix Amino Acid Sequence Phosphorylation Cells Cultured S phase Skin Multidisciplinary biology Cell Cycle Infant Newborn DNA replication Nuclear Proteins Biological Sciences Fibroblasts Chromatin Cyclin-Dependent Kinases Peptide Fragments Recombinant Proteins Cell biology biology.protein Origin recognition complex HeLa Cells |
| Zdroj: | Proceedings of the National Academy of Sciences. 96:6193-6198 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.96.11.6193 |
| Popis: | We have characterized HsCdc6, a human protein homologous to the budding yeast Cdc6p that is essential for DNA replication. We show that, unlike Cdc6p, the levels of HsCdc6 protein remain constant throughout the cell cycle in human cells. However, phosphorylation of HsCdc6 is regulated during the cell cycle. HsCdc6 is an excellent substrate for Cdk2 in vitro and is phosphorylated in vivo at three sites (Ser-54, Ser-74, and Ser-106) that are phosphorylated by Cdk2 in vitro , strongly suggesting that HsCdc6 is an in vivo Cdk substrate. HsCdc6 is nuclear in G 1 , but translocates to the cytoplasm at the start of S phase via Crm1-dependent export. An HsCdc6A1A2A3 mutant, which mimics unphosphorylated HsCdc6, is exclusively nuclear, and its expression inhibits initiation of DNA replication. An HsCdc6E1E2E3 mutant, which mimics phosphorylated HsCdc6, is exclusively cytoplasmic and is not associated with the chromatin/nuclear matrix fraction. Based on these results, we propose that phosphorylation of HsCdc6 by Cdks regulates DNA replication of at least two steps: first, by promoting initiation of DNA replication and, second, through nuclear exclusion preventing DNA rereplication. |
| Databáze: | OpenAIRE |
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