Lecture 7--cell motility

Myosin driven movement of actin filaments push

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Unformatted text preview: t of actin filaments push forward the membrane or promote contraction. 2. Actin monomers are inserted between the tip of actin filaments and the edge of the cell. Stress fibers provide the tension required for motility and underlie myosin-based contraction fibers that form when the cell is spread out and under tension, tend to span long distances in the cell. red structures? focal adhesions (could be integrin) stress fibers very responsive to tension Stress fibers (actin filaments) in the cytoplasm of cultured cells Burridge K, Wittchen ES (2013). The tension mounts: Stress fibers as force-generating mechanotransducers. J Cell Biol. 200(1):9-19. Molecular Structure of Stress Fibers very organied cell strucutres; stucutre of stress fibers: bundle of actin filaments Stress fibers contain actin, !-actinin, myosin and filamin. The actin filaments are arranged in an anti-parallel manner. The periodic arrangement of the components enables coordinated contraction to occur. Molecular Structure of Stress Fibers Alpha-actinin periodicity in a stress fiber Burridge K, Wittchen ES (2013). The tension mounts: Stress fibers as force-generating mechanotransducers. J Cell Biol. 200(1):9-19. An excellent source for learning about cell motility: http://www.mechanobio.info/ Go to: Browse Topics Skeletal Muscle contraction is mediated by myosin/ actin contaction Muscle bundle Muscle “cell” fiber what they have in common: head domain: where actin binding domain is and ATP activity The myosin family motor proteins that attche to the actin filaments and can move them around in the ATP dependent process in sarcomeres of muscles head domain, neck domain, coiled coil, have other head globular domains actin based transport myosin2: easily regulated Blembstatin: causes cell to bleb Figure 16-57 Molecular Biology of the Cell (© Garland Science 2008) make mutations in myosin and see its effect in binding and moving of actin Figure 16-56 Molecular Biology of the Cell (© Garland Science 2008) Stress fiber contraction is important for retracting the trailing edge as a cell migrates shrinks cell back again, release stress Endothelial cell migration during angiogenesis. Lamalice L, Le Boeuf F, Huot J. C...
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