BIOB10H3 Lecture Notes - Lecture 11: Dynein, Leading Edge, Myosin Light-Chain Kinase
4 Oct 2016
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Document Summary
Lecture 11- actin for cell shape changes contraction, cell motility, phagocytosis form structural backbone of microvilli intracellular transport. Actin cytoskeleton often enriched under pm (cell cortex) site of cell shape changes. Each monomer has tight binding sites for head-to-tail interactions with two other monomers, to form filaments. Actin filamentous [f] actin - microfilaments needs atp for polymerization arranges into a double helix. F-actin has polarity: - a pointed (-) end and barbed (+) end. Nucleation is the first step - forms trimer. Monomers added to either end reversible - allows actin filaments to be broken down when necessary. Actin is constantly assembling/ disassembling - called treadmilling . Rate at which monomers are added is proportional to their concentration. Barbed end grows 5 - 10 times faster than the pointed end. Actin bound to atp associates with the barbed ends; atp hydrolyzed to adp. Adp-actin dissociates from filaments more readily than atp-actin.
