Cytokinesis slide show 2008

Cytokinesis slide show 2008 - Cytokinesis Progression form...

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Cytokinesis Progression form Mitosis to Cytokinesis
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Exiting Mitosis The final stages of mitosis begin in anaphase when the mitotic spindle segregates the duplicated chromosomes. Mitotic exit is then completed by the disassembly of the spindle and packaging of the chromosomes into daughter nuclei. These events must occur in a strict order. Late mitosis is governed by two main mechanisms: 1.Dephosphorylation of cyclin-dependent kinase [CDK] substrates . 2.Destruction of the substrates of the Anaphase-promoting-complex [APC] ,894-903. Nov. 2007
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The Anaphase-Promoting Complex [APC] is a multi-subunit E3 Ubiquitin ligase. It binds two substrates: the protein target such as securin or cyclin and an E2 Ubiquitin-conjugating enzyme linked to ubiquitin, a 76-residue protein that targets ubiquinated proteins to the proteosome. What might be the consequences of mutations of one or more of its eleven subunits? 894-903. Nov. 2007
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Ubiquitin ligase
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The main targets for APC are securin and cyclins. Separase, released from Securin, allows sister chromatid separation. Destruction of cyclins results in a drop of Cdk activity. Phosphatases must be activated in late mitosis. Cdc14 is a phosphatase, found in the nucleolus where it is inactive bound to Net1. Phosphorylation of Net1 releases Cdc14. Action of the MEN complex fully activates Cdc14 leading to the final steps of mitosis. Notice that the MEN complex has a G-protein regulated by Cdc25. ,894-903. Nov 2007
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filaments. Cytokineses commences in anaphase and ends in telophase. A ring of actin and myosin forms the contractile ring leading to the cleavage furrow. The furrow rapidly deepens until it divides the cell in two. Ring formation depends on formins. Cytoplasmic vesicles fuse with the plasma membrane thus inserting new membrane to compensate for the increase in cell surface area seen in cell division . What is the origin of these vesicles? How do they know where to fuse? Mid-body is of remains of
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Cytokinesis slide show 2008 - Cytokinesis Progression form...

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