BIOL 401 Lecture Notes - Lecture 15: Cyclin-Dependent Kinase, Cyclin D, Cyclin E
28 Mar 2017
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If a cell is bombarded with mutations, that cell will program itself to die rather than take over the whole population. After a while our enzymatic machinery can"t keep up with the repairs and death programming, so cancer can begin. Contact inhibition: normal cells will stop proliferating in culture once they touch each other. Cancer cells never stop dividing because they won"t listen to growth inhibition cues. Cell cycle regulation: this is an extremely organized process. G1 s phase transition: considered the most important phase in safe replication (listen to 26:00). Cyclin d finds the target, cdk4 phosphorylates the target. Has to activate dna polymerase to reach s phase. Cyclin e and cdk2: g1 s. these drive the cell from g1 to s phase. There is no dna-directed dna polymerase yet, so until dna polymerase is here this won"t work. E2f: sits in cytoplasm during g1 phase. Bound to inhibitor called retinoblastoma, which is sequestering e2f.
