Biology 2382B Lecture Notes - Lecture 8: Spindle Apparatus, G2 Phase, G1 Phase
6 Feb 2017
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Further in the cell cycle, phosphatase comes and removes the phosphate off the mpf. (late g2) To prevent premature activation during s phase or g2 phase, (wee1 is a kinase that phosphorylates cdk leading to its inactivation (during s phase or. The phosphate needs to be removed as g2 is approached. Cdc25 is a phosphatase that removes the inhibitory phosphate group from cdk and promotes its activation. The green line is showing activity of mitotic cdk. The blue showing amount of mitotic cyclin protein (accumulates starting s phase but needs to peak in mitosis) Mpf activity depends on phosphorylation of two residues (tyr15 and thr161) in the catalytic cdk subunit. Wee1 inhibitory cdk kinase puts a phosphate on y15 to keep complex inactive. Further into the cell cycle, need to activate the complex: Cdc 25 (activating phosphatase), (at entrance to m phase) removes the inhibitory phosphate from y15: get a fully active mfp complex.
