PSY 214 Lecture Notes - Lecture 6: Phosphatidylinositol (3,4,5)-Trisphosphate, Ubiquitin Ligase, Anaphase-Promoting Complex
2 May 2016
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Discuss the two roles that we saw the. The anaphase promoting complex (apc/c) is an e3 ubiquitin ligase that helps carry out the process of ubiquitylation. Ubiquitylation is the covalent addition of a ubiquitin to a lysine on a target protein. It creates a polyubiquitin chain on the target protein, which is recognized by proteasomes which degrade the targeted protein. The apc/c is initially inactive and requires an activating subunit during mid-mitosis to activate it. It employs two main roles that trigger the metaphase-to- anaphase checkpoint: it controls the proteolysis of cyclins. In order to trigger the metaphase-to-anaphase checkpoint and enter anaphase, cyclins must be removed. This is done by the apc/c with the help of other enzymes called e1 and e2. All 3 enzymes work together in order to assemble a polyubiquitin chain on cyclins, which signals them for degradation by proteosomes: it controls the proteolysis of securins.
