Chk1 Rad53

Understanding How Cells Respond to DNA Damage May Lead to Better Cancer Treatments: "To prevent mutations that lead to uncontrolled growth, cells have special 'quality controlling' proteins that include dedicated scouts that look for damage to the DNA. When damaged DNA is detected, the scouts signal 'messenger' proteins, which place the cell on alert. When the alert is given, cell division is stopped, and the 'repair crew' is called. The 'scout' and 'messenger' proteins and the responses they regulate are part of what is called the checkpoint pathways. Once the damage is repaired, the cell is permitted to resume making a copy of the genetic information and proceed with cell division.
The researchers previously identified these 'scout' proteins that signal the presence of DNA damage and delay cell division, in order to allow time to repair the damage to the DNA. In their current paper, the same team of researchers describe the mechanism used by the signaling proteins which prevent the separation of chromosomes during mitosis to daughter cells. This inhibiting action occurs when damaged DNA has been detected. The task of preventing mitosis is shared between two proteins Chk1 and Rad53, which prevent chromosome separation (anaphase) and entry into the next cell cycle, respectively."