Biochemistry 3381A Lecture Notes - Lecture 12: Cytoskeleton, Microtubule, Cell Cortex
20 May 2020
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Lecture 12: The cytoskeleton
Yellow - microtubules. Star-shaped fashion.
Purple – actin filaments. Dense network throughout the cell and near the PM
Green – nuclei.
Cytoskeleton essential for life and involved in many fundamental processes.
Natural cytoskeleton-targeting toxins
Target the cytoskeleton to kill the organism.
Use the toxin to research the function of the cytoskeleton in the lab, or visualise in microscopy,
or used for cancer drugs.
Document Summary
Dense network throughout the cell and near the pm. Cytoskeleton essential for life and involved in many fundamental processes. They are dynamic structures that can assemble and disassemble rapidly in cells. Intermediate filaments are less dynamic and more stable structures compared to the other two. Nucleation of the filament is slow because stabilising interactions are few. Get bigger oligomers consisting of monomers which are stable to elongate. Reach a steady state, where the actin filament doesn"t grow anymore. Equilibrium where there is constantly actin monomers being incorporated and leaving the filament therefore it looks like zero growth. Association and dissociation rates are different and happen on opposing ends. Points of regulation of polymerisation dynamics by actin-binding proteins. Regulated by arsenal of different actin binding proteins. Sequester free actin monomers which can readily assemble when needed. Thymosin and profilin activate the binding of the monomer. Most monomers being sequestered by thymosin and being inhibited by assembly.
