Activated CHK1 then plays pivotal roles in coordinating cellular responses to replication stress, slowing S-phase progression by suppressing inappropriate firing of replication origins, maintaining fork integrity, facilitating resolution of stalled forks and triggering G2/M arrest.
We cannot also exclude sporadic collapse of a higher number of replication forks in Tipin-depleted extract, consistent with the role of Tipin in maintaining fork stability (Chou and Elledge, 2006; Errico et al, 2007).
It is well recognized that, in response to replication stress, the main function of the replication checkpoint is to maintain fork integrity, promoting fork recovery and then replication restart.
These effects were anticipated because these conditions are known to induce a replication arrest and are therefore supportive of a role for ATR in maintaining fork stability.
Yeast orthologues of Tim and Tipin maintain replication fork stability at fork barriers, but the precise mechanism of these proteins and the function of the fork barriers remain enigmatic.
Chk1 activity is required to maintain replication fork stability and inhibition of Chk1 leads to replication fork collapse and the generation of "new" DNA strand breaks.
While maintaining embedding in a fork of Gecko is theoretically possible, we don't have the manpower for a sustained effort of that kind.
The ATR protein kinase senses problems during DNA replication and, in the event of stalled DNA replication, maintains replication fork stability and prevents cell cycle progression.
Each fork maintains a record of how far it has travelled and, if the movement would cause a JBFork to exceed its stall distance, it stalls irreversibly.
These studies establish that Tim-Tipin-Claspin function together as components of the mammalian and yeast replisome that are required for maintaining replication fork stability at programmed pause sites and during conditions of DNA damage.
