Bruck I, et al. (2011) Enabling association of the GINS protein tetramer with the mini chromosome maintenance (Mcm)2-7 protein complex by phosphorylated Sld2 protein and single-stranded origin DNA. J Biol Chem 286(42):36414-26
Abstract: The Cdc45-Mcm2-7-GINS (CMG) complex is the replication fork helicase in eukaryotes. Synthetic lethal with Dpb11-1 (Sld2) is required for the initiation of DNA replication, and the S phase cyclin-dependent kinase (S-CDK) phosphorylates Sld2 in vivo. We purified components of the replication initiation machinery and studied their interactions in vitro. We found that unphosphorylated or CDK-phosphorylated Sld2 binds to the mini chromosome maintenance (Mcm)2-7 complex with similar efficiency. Sld2 interaction with Mcm2-7 blocks the interaction between GINS and Mcm2-7. The interaction between CDK-phosphorylated Sld2 and Mcm2-7 is substantially inhibited by origin single-stranded DNA (ssDNA). Furthermore, origin ssDNA allows GINS to bind to Mcm2-7 in the presence of CDK-phosphorylated Sld2. However, unphosphorylated Sld2 blocks the interaction between GINS and Mcm2-7 even in the presence of origin ssDNA. We identified a mutant of Sld2 that does not bind to DNA. When this mutant is expressed in yeast cells, cell growth is severely inhibited with very slow progression into S phase. We propose a model wherein Sld2 blocks the interaction between GINS and Mcm2-7 in vivo. Once origin ssDNA is extruded from the Mcm2-7 ring and CDK phosphorylates Sld2, the origin ssDNA binds to CDK-phosphorylated Sld2. This event may allow the interaction between GINS and Mcm2-7 in vivo. Thus, CDK phosphorylation of Sld2 may be important to release Sld2 from Mcm2-7, thereby allowing GINS to bind Mcm2-7. Furthermore, origin ssDNA may stimulate the formation of the CMG complex by alleviating inhibitory interactions between Sld2 with Mcm2-7.
|Status: Published||Type: Journal Article||PubMed ID: 21868389|
Topics addressed in this paper
Number of different genes curated to this paper: 12
- To find other papers on a gene and topic, click on the colored ball in the appropriate box.
- displays other papers with information about that topic for that gene.
- displays other papers in SGD that are associated with that topic.
The topic is addressed in these papers but does not describe a specific gene or chromosomal feature.
- To go to the Locus page for a gene, click on the gene name.
|Topics||Genes linked to topics (#1 - 10 )|
|Protein-Nucleic Acid Interactions|
|Topics||Genes linked to topics (#11 - 12 )|