BIO315H5 Lecture Notes - Lecture 21: Small Gtpase, P21, Mitosis
Document Summary
Ran-gtp releases certain proteins from inhibiting complexes and stabilizes microtubules and promotes local nucleation. Explain figure 17. 28: spindle self-organization by motor proteins. Mitotic chromosomes stimulate the local activation of proteins that nucleate and promote the formation of microtubules in the vicinity of the chromosomes. Kinesin- 5 motor proteins organize these microtubules into antiparallel bundles, while plus end directed kinesins 4 and 10 link the microtubules to chromosome arms and push minus ends away from the chromosomes. Dynein and kinesin 14 motors together with numerous other proteins, focus these minus ends into a pair of spindle poles. A mitogen is a chemical substance that encourages a cell to commence cell division, triggering mitosis. (mechanism for cell cycle control) An exam of overcoming blockage in the cell cycle is outlined in figure 17. 61. Explain figure 17. 61: mitogen stimulation of cell cycle entry. Mitogens bind to cell surgace receptors to initiate intracellular signalling pathways.
