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Cyclin-dependent Kinase 1
Cyclin-dependent kinase 1 also known as CDK1 or cell division cycle protein 2 homolog is a highly conserved protein that functions as a serine/threonine protein kinase, and is a key player in cell cycle regulation. It has been highly studied in the budding yeast ''S. cerevisiae'', and the fission yeast ''S. pombe'', where it is encoded by genes ''cdc28'' an''cdc2'' respectively. With its cyclin partners, Cdk1 forms complexes that phosphorylate a variety of target substrates (over 75 have been identified in budding yeast); phosphorylation of these proteins leads to cell cycle progression. Structure Cdk1 is a small protein (approximately 34 kilodaltons), and is highly conserved. The human homolog of Cdk1, ''CDK1'', shares approximately 63% amino-acid identity with its yeast homolog. Furthermore, human ''CDK1'' is capable of rescuing fission yeast carrying a ''cdc2'' mutation. Cdk1 is comprised mostly by the bare protein kinase motif, which other protein kinases share. Cdk1, li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pom1
Pom1 is a polarity protein kinase in fission yeast, ''Schizosaccharomyces pombe'' (''S. pombe''), that localizes to cell ends and regulates cell division. As the cell lengthens, the level of Pom1 in the middle declines, which triggers mitosis.Bahler, J., and Pringle, J.R. “Pom1p, a fission yeast protein kinase that provides positional information for both polarized growth and cytokinesis.” Genes and Development 12, 1356-1370 (1998). The genebr>''pom1''codes for a protein 1087 amino acids long with the protein kinase domain likely located at the carboxyl terminus. Pom1 regulates a signaling pathway that includes Cdk1 and ultimately regulates mitotic entry.Moseley, J.B., Mayeux, A., Paoletti, A. and Nurse, P. “A spatial gradient coordinates cell size and mitotic entry in fission yeast.” Nature 459, 857-861 (2009). Cells with mutant pom1 form a septa and growth zone, but show a host of abnormalities including misplaced or misoriented septa, bi-polar growth replaced with r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maturation Promoting Factor
Maturation-promoting factor (abbreviated MPF, also called mitosis-promoting factor or M-Phase-promoting factor) is the cyclin-Cdk complex that was discovered first in frog eggs. It stimulates the mitotic and meiotic phases of the cell cycle. MPF promotes the entrance into mitosis (the M phase) from the G2 phase by phosphorylating multiple proteins needed during mitosis. MPF is activated at the end of G2 by a phosphatase, which removes an inhibitory phosphate group added earlier. The MPF is also called the M phase kinase because of its ability to phosphorylate target proteins at a specific point in the cell cycle and thus control their ability to function. Discovery In 1971, two independent teams of researchers ( Yoshio Masui and Clement Markert, as well as Dennis Smith and Robert Ecker) found that frog oocytes arrested in G2 could be induced to enter M phase by microinjection of cytoplasm from oocytes that had been hormonally stimulated with progesterone. Because the entry of oo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cdc25
Cdc25 is a dual-specificity phosphatase first isolated from the yeast ''Schizosaccharomyces pombe'' as a cell cycle defective mutant. As with other cell cycle proteins or genes such as Cdc2 and Cdc4, the "cdc" in its name refers to "cell division control". Dual-specificity phosphatases are considered a sub-class of protein tyrosine phosphatases. By removing inhibitory phosphate residues from target cyclin-dependent kinases (Cdks), Cdc25 proteins control entry into and progression through various phases of the cell cycle, including mitosis and S ("Synthesis") phase. Function in activating Cdk1 Cdc25 activates cyclin dependent kinases by removing phosphate from residues in the Cdk active site. In turn, the phosphorylation by M-Cdk (a complex of Cdk1 and cyclin B) activates Cdc25. Together with Wee1, M-Cdk activation is switch-like. The switch-like behavior forces entry into mitosis to be quick and irreversible. Cdk activity can be reactivated after dephosphorylation by Cdc25. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperphosphorylation
Hyperphosphorylation occurs when a biochemical with multiple phosphorylation sites is fully saturated. Hyperphosphorylation is one of the signaling mechanisms used by the cell to regulate mitosis. When these mechanisms fail, developmental problems or cancer are a likely outcome. The mechanism appears to be largely conserved throughout eukaryote species. The dynamics of mitosis are similar to a state machine. In a healthy cell, checkpoints between phases permit a new phase to begin only when the previous phase is complete and successful. At these checkpoints, gatekeeper molecules block or allow events, depending on their level of phosphorylation. Kinases are responsible for adding phosphate groups and phosphatases for removing them. Cyclins are molecules that manage the timing of cell cycle events. Cyclin dependent kinases pair up with cyclins to become operational. Cyclins are named because they are created or destroyed at predetermined points within the cell cycle. Kinase inhi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubiquitin C
Polyubiquitin-C is a protein encoded by the ''UBC'' gene in humans. Polyubiquitin-C is one of the sources of ubiquitin, along with UBB, UBA52, and RPS27A. ''UBC'' gene is one of the two stress-regulated polyubiquitin genes (''UBB'' and ''UBC'') in mammals. It plays a key role in maintaining cellular ubiquitin levels under stress conditions. Defects of ''UBC'' gene could lead to mid-gestation embryonic lethality. Structure Gene ''UBC'' gene is located at chromosome 12q24.3, consisting of 2 exons. The promoter of the ''UBC'' gene contains putative heat shock elements ( HSEs), which mediates UBC induction upon stress. ''UBC'' gene differs from ''UBB'' gene in the number of Ub coding units they contain. Nine to ten Ub units were in the ''UBC'' gene. Protein In polyubiquitin-C, the C-terminus of a given ubiquitin molecule is covalently conjugated to either the N-terminal residue or one of seven lysine residues of another ubiquitin molecule. Different linking of ubiquitin chains r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LATS1
Large tumor suppressor kinase 1 (LATS1) is an enzyme that in humans is encoded by the ''LATS1'' gene. It has been associated with the Hippo signaling pathway, where it phosphorylates YAP and TAZ to inactivate their function. The protein encoded by this gene is a putative serine/threonine kinase that localizes to the mitotic apparatus and complexes with cell cycle controller CDC2 kinase in early mitosis. The protein is phosphorylated in a cell-cycle dependent manner, with late prophase phosphorylation remaining through metaphase. The N-terminal region of the protein binds CDC2 to form a complex showing reduced histone H1 kinase activity, indicating a role as a negative regulator of CDC2/cyclin A. In addition, the C-terminal kinase domain binds to its own N-terminal region, suggesting potential negative regulation through interference with complex formation via intramolecular binding. Biochemical and genetic data suggest a role as a tumor suppressor. This is supported by studies in k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GADD45A
Growth arrest and DNA-damage-inducible protein GADD45 alpha is a protein that in humans is encoded by the ''GADD45A'' gene. Function This gene is a member of a group of genes, the GADD45 genes, whose transcript levels are increased following stressful growth arrest conditions and treatment with DNA-damaging agents (mutagens). The DNA damage-induced transcription of this gene is mediated by both p53-dependent and -independent mechanisms. The protein encoded by this gene responds to environmental stresses by mediating activation of the p38/JNK pathway via MTK1/MEKK4 kinase. Applications The fact that expression of this gene is an indicator of DNA damage has been exploited to construct an ''in vitro'' test for mutagenicity, the GADD45a-GFP GreenScreen HC assay. This assay consists of a cell line which has been engineered so that expression of GADD45A will lead to expression of green fluorescent protein, which can easily be detected. To test a substance for mutagenicity, it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fanconi Anemia, Complementation Group C
Fanconi anemia group C protein is a protein that in humans is encoded by the ''FANCC'' gene. Structure Function The protein encoded by this gene delays the onset of apoptosis and promotes homologous recombination repair of damaged DNA. Mutations in this gene result in Fanconi anemia. A nuclear complex containing FANCC protein (as well as FANCA, FANCF and FANCG) is essential for the activation of the FANCD2 protein to the mono-ubiquitinated isoform. In normal, non-mutant, cells FANCD2 is mono-ubiquinated in response to DNA damage. FANCC together with FANCE acts as the substrate adaptor for this reaction Activated FANCD2 protein co-localizes with BRCA1 (breast cancer susceptibility protein) at ionizing radiation-induced foci and in synaptonemal complexes of meiotic chromosomes. Activated FANCD2 protein may function prior to the initiation of meiotic recombination, perhaps to prepare chromosomes for synapsis, or to regulate subsequent recombination events. FANCC(-/-) m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DAB2
Disabled homolog 2 is a protein that in humans is encoded by the ''DAB2'' gene. Function DAB2 mRNA is expressed in normal ovarian epithelial cells but is down-regulated or absent from ovarian carcinoma cell lines. The 770-amino acid predicted protein has an overall 83% identity with the mouse p96 protein, a putative mitogen-responsive phosphoprotein; homology is strongest in the amino-terminal end of the protein in a region corresponding to the phosphotyrosine interaction domain. The down-regulation of DAB2 may play an important role in ovarian carcinogenesis. This gene was initially named DOC2 (for Differentially expressed in Ovarian Cancer) and is distinct from the DOC2A and DOC2B genes (for double C2-like domains, alpha and beta). Interactions DAB2 has been shown to interact with: * C-src tyrosine kinase, * Cdk1, * DAB2IP, * DVL2, * DVL3, * LRP2, * MYO6, * Mothers against decapentaplegic homolog 2, * Mothers against decapentaplegic homolog 3 * PIN1 Peptidyl- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDKN3
Cyclin-dependent kinase inhibitor 3 is an enzyme that in humans is encoded by the ''CDKN3'' gene. The protein encoded by this gene belongs to the dual specificity protein phosphatase family. It was identified as a cyclin-dependent kinase inhibitor, and has been shown to interact with, and dephosphorylate CDK2 kinase, thus prevent the activation of CDK2 kinase. This gene was reported to be deleted, mutated, or overexpressed in several kinds of cancers. Interactions CDKN3 has been shown to interact with Cyclin-dependent kinase 2, Cdk1 Cyclin-dependent kinase 1 also known as CDK1 or cell division cycle protein 2 homolog is a highly conserved protein that functions as a serine/threonine protein kinase, and is a key player in cell cycle regulation. It has been highly studied in t ... and MS4A3. References Further reading * * * * * * * * * * * * * * * External links * * {{gene-14-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin E1
G1/S-specific cyclin-E1 is a protein that in humans is encoded by the ''CCNE1'' gene. Function The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. This cyclin forms a complex with and functions as a regulatory subunit of CDK2, whose activity is required for cell cycle G1/S transition. This protein accumulates at the G1-S phase boundary and is degraded as cells progress through S phase. Overexpression of this gene has been observed in many tumors, which results in chromosome instability, and thus may contribute to tumorigenesis. This protein was found to associate with, and be involved in, the phosphorylation of NPAT protein (nuclear protein mapped to the ATM locus), which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
