Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Saccharomyces cerevisiae CDC7 gene encodes a protein kinase that functions in DNA replication, repair, and meiotic recombination. The sequence of several temperature-sensitive (ts) cdc7 mutations was determined and correlated with protein kinase consensus domain structure. The positions of these ts alleles suggests some general principles for predicting ts protein kinase mutations. Pedigree segregation lag analysis demonstrated that all of the mutant proteins are less active or less stable than wild-type Cdc7p. Two new mutations were constructed, one by site-directed and the other by insertional mutagenesis. All of the cdc7 mutants were assayed for induced mutagenesis in response to mutagenic agents at the permissive temperature. Some cdc7 mutants were found to be hypomutable, while others are hypermutable. The differences in mutability are observed most clearly when log phase cells are used. Both hypo- and hypermutability are recessive to wild type. Cdc7p may participate in DNA repair by phosphorylating repair enzymes or by altering chromatin structure to allow accessibility to DNA lesions.
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PMID:Molecular genetic studies of the Cdc7 protein kinase and induced mutagenesis in yeast. 139 63

A 48-kDa protein from the budding yeast Saccharomyces cerevisiae is antigenically and structurally similar to S-antigen from retina. Eight anti-S-antigen monoclonal antibodies, directed against distinct epitopes, cross-reacted with a yeast 48-kDa protein. Structural similarity between the bovine and yeast proteins was further demonstrated by comparison of tryptic peptide fragments containing one of these epitopes. This 48-kDa yeast protein appears to be a component of the replicative complex of the cell. It was found associated with immunoaffinity-purified yeast DNA polymerase I-primase and with yeast DNA-replicative complex. The 48-kDa protein was phosphorylated by a protein kinase activity endogenous to the replicative complex preparation. This phosphorylation was dependent on the cell division cycle gene CDC7. In addition, authentic bovine S-antigen, when added to yeast DNA polymerase I-primase, stimulated polymerase activity. These findings suggest that the yeast S-antigen-like protein may play a role in replication, and they raise the possibility that it may be involved in traversal of the G1/S boundary of the cell cycle.
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PMID:A 48-kDa, S-antigen-like phosphoprotein in yeast DNA-replicative complex preparations. 186 Aug 66

The product of the CDC7 gene of Saccharomyces cerevisiae has multiple cellular functions, being needed for the initiation of DNA synthesis during mitosis as well as for synaptonemal complex formation and commitment to recombination during meiosis. The CDC7 protein has protein kinase activity and contains the conserved residues characteristic of the protein kinase catalytic domain. To determine which of the cellular functions of CDC7 require this protein kinase activity, we have mutated some of the conserved residues within the CDC7 catalytic domain and have examined the ability of the mutant proteins to support mitosis and meiosis. The results indicate that the protein kinase activity of the CDC7 gene product is essential for its function in both mitosis and meiosis and that this activity is potentially regulated by phosphorylation of the CDC7 protein.
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PMID:CDC7 protein kinase activity is required for mitosis and meiosis in Saccharomyces cerevisiae. 186 80

The cell division cycle gene CDC15 is essential for the late nuclear division in the yeast Saccharomyces cerevisiae. The amino acid sequence of the 974 amino acids/110 kDa CDC15 gene product, as deduced from the nucleotide sequence, includes an aminoterminal protein kinase domain which contains a primary sequence mosaic showing patterns specific for protein serine/threonine kinases besides those for protein tyrosine kinases. Many protein kinases non-essential for growth are known. CDC15 represents an essential protein kinase like CDC7 and CDC28. A carboxyterminal deletion of 32 amino acids renders the protein inactive.
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PMID:CDC15, an essential cell cycle gene in Saccharomyces cerevisiae, encodes a protein kinase domain. 188 51

The mating-type genes at MAT in Saccharomyces cerevisiae are expressed, whereas the same genes located at HML and HMR are transcriptionally repressed. The DNA element responsible for repression at HMR has been termed a silencer and contains an autonomous replication sequence, a binding site for GRFI/RAPI, and a binding site for ABFI. A double-mutant HMR-E silencer that contains single nucleotide substitutions in both the GRFI/RAPI- and ABFI-binding sites no longer binds either factor in vitro, nor represses transcription at HMR in vivo. In MAT alpha cells, this derepression of a information results in a nonmating phenotype. Second-site suppressor mutations were isolated that restored the alpha mating phenotype to MAT alpha cells containing the double-mutant silencer. One of these suppressors, designated sas1-1, conferred a temperature-sensitive lethal phenotype to the cell. SAS1 was found to be identical to CDC7, a gene which encodes a protein kinase required for the initiation of DNA replication. This new allele of CDC7 was designated cdc7-90. cdc7-90 restored the alpha mating phenotype by restoring silencing. The original allele of CDC7, isolated on the basis of the cell cycle phenotype it confers, also restored silencing, and overexpression of CDC7 interfered with silencing. cdc7-90 did not restore detectable binding of GRFI/RAPI or ABFI to the double-mutant silencer in vitro. These results indicate that a reduced level of CDC7 function restores silencing to a locus defective in binding two factors normally required for silencing.
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PMID:A role for CDC7 in repression of transcription at the silent mating-type locus HMR in Saccharomyces cerevisiae. 199 Feb 68

A protein kinase activity was identified in preparations of DNA-replicative complex from the budding yeast Saccharomyces cerevisiae. The activity phosphorylated only a few of the endogenous proteins in the replicative fraction, and it displayed a marked preference for a 48-kDa polypeptide. Despite this relative specificity, the protein kinase activity was capable of utilizing exogenously added histone as substrate. The 48-kDa polypeptide was phosphorylated on serine residue(s) exclusively by the endogenous activity in the replicative-complex preparation. The activity was not stimulated by cAMP, cGMP, Ca2+/phosphatidylserine/diacylglycerol, or Ca2+/calmodulin. It did not utilize Ca2+ or Zn2+ in the place of Mg2+, and Mn2+ was only 22% as effective in fulfilling the divalent-cation requirement. Most importantly, the protein kinase activity was heat-sensitive in replicative fractions from the cell division cycle 7 (cdc7) mutant, which arrests at or close to the G1/S boundary of the cell cycle at restrictive temperature. Thus, the activity is CDC7-dependent. An effect of heat treatment on replicating activity in the replicative fraction from cdc7 cells was also found. This result and the finding that the protein kinase activity copurified with replicating activity in the preparations suggest that the CDC7 gene product and the protein kinase activity, whether or not they are the same entity, interact with yeast replicative complex. All of these results raise the possibility that phosphorylation of components of the replication machinery may play a role in the control of initiation of DNA replication during the cell cycle. It is possible that the phosphorylation observed is part of a protein kinase cascade that regulates progress through the G1 phase of the cell cycle.
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PMID:CDC7-dependent protein kinase activity in yeast replicative-complex preparations. 328 Nov 61

The product of the CDC7 gene of Saccharomyces cerevisiae appears to have multiple roles in cellular physiology. It is required for the initiation of mitotic DNA synthesis. While it is not required for the initiation of meiotic DNA replication, it is necessary for genetic recombination during meiosis and for the formation of ascospores. It has also been implicated in an error-prone DNA repair pathway. Plasmids capable of complementing temperature-sensitive cdc7 mutations were isolated from libraries of yeast genomic DNA in the multicopy plasmid vectors YRp7 and YEp24. The complementing activity was localized within a 3.0-kilobase genomic DNA fragment. Genetic studies that included integration of the genomic insert at or near the CDC7 locus and marker rescue of four cdc7 alleles proved that the cloned fragment contains the yeast chromosomal CDC7 gene. The RNA transcript of CDC7 is about 1,700 nucleotides. Analysis of the nucleotide sequence of a 2.1-kilobase region of the cloned fragment revealed the presence of an open reading frame of 1,521 nucleotides that is presumed to encode the CDC7 protein. Depending on which of two possible ATG codons initiates translation, the calculated size of the CDC7 protein is 58.2 or 56 kilodaltons. Comparison of the predicted amino acid sequence of the CDC7 gene product with other known protein sequences suggests that CDC7 encodes a protein kinase.
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PMID:Molecular characterization of cell cycle gene CDC7 from Saccharomyces cerevisiae. 353 6

The Saccharomyces cerevisiae CDC7 gene encodes a protein kinase that functions in three aspects of DNA metabolism: replication, repair, and meiotic recombination. It is likely that these functions overlap and share common elements. The cell cycle dependence of Cdc7 associated DNA repair was examined by UV irradiating a wild type and hypomutable cdc7-7 strain throughout the cell cycle. Both the wild type strain and the cdc7-7 mutant stain delay entry into S phase by 40-60 min when exposed to UV mutagenesis. Cells in G1 are the most sensitive to lethal UV damage while cells in S phase sustain fewer lethal hits. The yield of mutants is greatest for the CDC7 wild type strain when S phase cells are mutagenized. This peak of induced mutagenesis is absent in the cdc7-7 strain. Cdc7 protein may be required for error-prone DNA repair or for translesion error-prone DNA replication and not for the checkpoints in G1 phase. Because Cdc28 protein kinase and Dbf4 protein, a Cdc7 kinase regulator, are also important for induced mutagenesis and the CDC7 promoter is not induced in response to DNA damage, Cdc7 protein kinase may be regulated post-translationally following DNA damage, in the same manner as it is regulated during the cell cycle.
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PMID:Cell cycle regulation of induced mutagenesis in yeast. 760 96

In Saccharomyces cerevisiae, START has been shown to comprise a series of tightly regulated reactions by which the cellular environment is assessed and under appropriate conditions, cells are commited to a further round of mitotic division. The key effector of START is the product of the CDC28 gene and the mechanisms by which the protein kinase activity of this gene product is regulated at START are well characterized. This is in contrast to the events which follow p34CDC28 activation and the way in which progress to S phase is achieved, which are less clear. We suggest two possible models to describe the regulation of these events. Firstly, it is conceivable that the only post-START targets of the p34CDC28/G1 cyclin kinase complex are components of the SBF and DSC1 transcription factors. This would require that either SBF or DSC1 regulates CDC4 function either directly by activating the transcription of CDC4 itself or else indirectly by activating the transcription of a mediator of CDC4 function in a manner analogous to the way in which the control of CDC7 function may be mediated by transcriptional regulation of DBF4 (Jackson et al., 1993). Potential regulatory effectors of CDC4 function include SCM4, which suppresses cdc4 mutations in an allele-specific manner (Smith et al., 1992) or its homologue HFS1 (J. Hartley & J. Rosamond, unpublished). This possibility is supported by the finding that CDC4 has no upstream SCB or MCB elements, whereas SCM4 and HFS1 have either an exact or close match to the SCB. This model would further require that genes needed for bud emergence and spindle pole body duplication are also subject to transcriptional regulation by DSC1 or SBF. An alternative model is that the p34CDC28/G1 cyclin complexes have several targets post-START, one being DSC1 and the others being as yet unidentified components of the pathways leading to CDC4 function, spindle pole body duplication and bud emergence. This model could account for the functional redundancy observed amongst the G1 cyclins with the various cyclins providing substrate specificity for the kinase complex. We suggest that a complex containing Cln3 protein is primarily responsible for, and acts most efficiently on, the targets containing Swi6 protein (SBF and DSC1), with complexes containing other G1 cyclins (Cln1 and/or Cln2 proteins) principally involved in activating the other pathways. However, there must be overlap in the function of these complexes with each cyclin able to substitute for some or all of the functions when necessary, albeit with differing efficiencies. This hypothesis is supported by several observations.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Starting to cycle: G1 controls regulating cell division in budding yeast. 827 39

The yeast Cdc7 function is required for the G1/S transition and is dependent on passage through START, a point controlled by the Cdc28/cdc2/p34 protein kinase. CDC7 encodes a protein kinase activity, and we now show that this kinase activity varies in the cell cycle but that protein levels appear to remain constant. We present several lines of evidence that periodic activation of CDC7 kinase is at least in part through phosphorylation. First, the kinase activity of the Cdc7 protein is destroyed by dephosphorylation of the protein in vitro with phosphatase. Second, Cdc7 protein is hypophosphorylated and inactive as a kinase in extracts of cells arrested at START but becomes active and maximally phosphorylated subsequent to passage through START. The phosphorylation pattern of Cdc7 protein is complex. Phosphopeptide mapping reveals four phosphopeptides in Cdc7 prepared from asynchronous yeast cells. Both autophosphorylation and phosphorylation in trans appear to contribute to this pattern. Autophosphorylation is shown to occur by using a thermolabile Cdc7 protein. A protein in yeast extracts can phosphorylate and activate Cdc7 protein made in Escherichia coli, and phosphorylation is thermolabile in cdc28 mutant extracts. Cdc7 protein carrying a serine to alanine change in the consensus recognition site for Cdc28 kinase shows an altered phosphopeptide map, suggesting that this site is important in determining the overall Cdc7 phosphorylation pattern.
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PMID:Regulation of Saccharomyces cerevisiae CDC7 function during the cell cycle. 838 76


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