Biology 2382B Lecture Notes - Lecture 7: Cyclin-Dependent Kinase 1, G1 Phase, G2 Phase
Document Summary
When active it triggers many processes in mitosis. Cdc2 (cdk); constitutively expressed; activity peaks as m begins. Cdc13 (cyclin); levels increase during cell cycle and peak at m creating heterodimer. Ubiquitin ligase; recognizes destruction box (9 amino acid sequence) on cyclins and targets them for degradation. Human cdk can be introduced into yeast and it will complement the deficiency. Cell cycle inferred by size of the bud. Promote transcription of genes required for g1/s/g2 progression (i. e. cyclins) and for dna synthesis. Promote transcription of genes that induce cell cycle arrest (check point genes) Gets stuck on proteins (cyclin) targeted for degradation. P53; constitutively made but degraded all the time; can be activated that much quicker via phosphorylation. Dna damage leads to phosphorylation and stabilization of p53 (a transcription factor) P53 activates the transcription of p21 (a cdk inhibitor protein, cip) Cip inhibits all cyclin-cdk complexes and halts cell cycle (mpf)