It is right before a checkpoint, which in the parlance of Cirque means a rehearsal attended by the artistic brass, including Mr. Laliberté.
Thus Rcd might be part of a checkpoint which causes a delay in cell division until multimers are converted into monomers, and Rcd seems to play a role in plasmid maintenance, which is functionally independent of dimer resolution [ 14].
Checkpoint kinase 1 (Chk1), a serine/threonine protein kinase, plays an important role in G2/M checkpoint, which is a key regulator in response to DNA damage.
We have described a representation of the role of phosphorylation for a few core proteins in the spindle checkpoint, which we developed using a combination of text mining, data mining, ontologies and network visualization tools.
As a result, abrogation of the G2/M checkpoint would be effective in promoting cell cycle arrest or apoptosis of p53-mutant cancer cells in the G2/M checkpoint which have escaped the fate of cell cycle arrest or apoptosis in the G1/M checkpoint.
In the latter case, we attribute CDC28 haploproficiency (at least, in part) to the reduced activity of cell-cycle checkpoints (in particular, the spindle checkpoint), which are redundant in the absence of a cell cycle defect.
Our results are consistent with previous reports suggesting that hESCs have a robust and active G2/M checkpoint and an absent G1/S checkpoint, which first appears in NPs after differentiation of hESCs [4], [32], [35].
Other mechanistic parallels remain to be tested, in particular, the role of DDK in the pre-meiotic replication checkpoint, which we identified as a central player in coupling DNA replication with DSB formation in budding yeast.
Defects in FAS1 lead to a halt in the progression through G2 by up-regulating several genes involved in the G2 DNA checkpoint, which it accomplishes by changing epigenetic marks of their promoters [ 24].
The Cdc25p phosphatase is an activator of the cyclin dependent kinase Cdk2p and when over-produced it results in a bypass of the G2/M checkpoint, which ensures that DNA replication is completed before the M phase is initiated.
