Checkpoints, Cancer
checkpoint
- specific points where cell cycle can be put on hold
•
2 irreversible points - replication of genetic material, sister chromatid separation
•
kinase - adds phosphate
•
phosphatase - takes away phosphate
•
phosphorylation/dephosphorylation >> activate/deactivate proteins >> drives cell cycle
•
cyclin - proteins displaying characteristic patterns of synthesis/degradation like the cell
cycle
•
cyclin-dependent kinase
(Cdk) - enzyme that controls passage through the checkpoints
•
multicellular organisms respond to more external signals and use more Cdk’s than
unicellular organisms
G1/S checkpoint
- main point where the cell decides whether or not to divide
•
links cell division to cell growth
•
aka “restriction point” (R point) in animals
•
aka “start” in yeasts
•
decision to replicate genome >> decision to replicate
•
internal signals - nutritional cell state, cell size
•
external signals - factors that promote cell growth/division
G2/M checkpoint
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- Fall '10
- Orlando,Rebecca
- Biology, Cell Cycle
-
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