G2 phase, Gap 2 phase, or Growth 2 phase, is the third subphase of interphase in the cell cycle directly preceding mitosis. It follows the successful completion of S phase, during which the cell’s DNA is replicated. G2 phase ends with the onset of prophase, the first phase of mitosis in which the cell’s chromatin condenses into chromosomes.
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 cycle". 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.
CHEK2 is a tumor suppressor gene that encodes the protein CHK2, a serine-threonine kinase. CHK2 is involved in DNA repair, cell cycle arrest or apoptosis in response to DNA damage. Mutations to the CHEK2 gene have been linked to a wide range of cancers.
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 and cdc2, respectively. With its cyclin partners, Cdk1 forms complexes that phosphorylate a variety of target substrates ; phosphorylation of these proteins leads to cell cycle progression.
Checkpoint kinase 1, commonly referred to as Chk1, is a serine/threonine-specific protein kinase that, in humans, is encoded by the CHEK1 gene. Chk1 coordinates the DNA damage response (DDR) and cell cycle checkpoint response. Activation of Chk1 results in the initiation of cell cycle checkpoints, cell cycle arrest, DNA repair and cell death to prevent damaged cells from progressing through the cell cycle.
G2/mitotic-specific cyclin-B1 is a protein that in humans is encoded by the CCNB1 gene.
G1/S-specific cyclin-D3 is a protein that in humans is encoded by the CCND3 gene.
M-phase inducer phosphatase 1 also known as dual specificity phosphatase Cdc25A is a protein that in humans is encoded by the cell division cycle 25 homolog A (CDC25A) gene.
WEE1 homolog , also known as WEE1, is a protein which in humans is encoded by the WEE1 gene.
Cyclin-A1 is a protein that in humans is encoded by the CCNA1 gene.
14-3-3 protein beta/alpha is a protein that in humans is encoded by the YWHAB gene.
M-phase inducer phosphatase 3 is an enzyme that in humans is encoded by the CDC25C gene.
14-3-3 protein epsilon is a protein that in humans is encoded by the YWHAE gene.
Serine/threonine-protein phosphatase 2A regulatory subunit B is an enzyme that in humans is encoded by the PPP2R4 gene.
Polo-like kinase 3 (Drosophila), also known as PLK3, is an enzyme which in humans is encoded by the PLK3 gene.
Cyclin-dependent kinase 4 inhibitor C is an enzyme that in humans is encoded by the CDKN2C gene.
Cyclin-G1 is a protein that in humans is encoded by the CCNG1 gene.
Cell division protein kinase 3 is an enzyme that in humans is encoded by the CDK3 gene.
Maternal embryonic leucine zipper kinase (MELK) is an enzyme that in humans is encoded by the MELK gene. MELK is a serine/threonine kinase belonging to the family of AMPK/Snf1 protein kinases. MELK was first identified present as maternal mRNA in mouse embryos. MELK expression is elevated in a number of cancers and is an active research target for pharmacological inhibition.
Wee1 is a nuclear kinase belonging to the Ser/Thr family of protein kinases in the fission yeast Schizosaccharomyces pombe. Wee1 has a molecular mass of 96 kDa and is a key regulator of cell cycle progression. It influences cell size by inhibiting the entry into mitosis, through inhibiting Cdk1. Wee1 has homologues in many other organisms, including mammals.
