Biology 2382B Lecture Notes - Tubulin, Microtubule, Centriole
9 Mar 2014
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Document Summary
How is cellular movement achieved: cellular trafficking of organelles, cell migration. Intricate network of protein filaments that extend throughout the cytoplasm. Cytoskeleton: microtubules 25 nm, microfilaments 7-9 nm, cytoskeleton roles. Functions often require energy o: organelle/protein trafficking, cilia/flagella, mitosis/cytokinesis, muscle contraction, cell adhesion, cell migration, extravasation. The organization of tubulin subunits in a microtubule the dimers are aligned end to end into protofilaments, which pack side by side to form the wall of the microtubule. The protofilaments are slightly staggered so that a-tubulin in one protofilament is in contact with a-tubulin in the neighboring protofilaments, except at the seam, where an a-subunit contacts a -subunit. The microtubule displays a structural polarity in that subunits are added preferentially at the end where -subunits are exposed. As the polymer (protofilament) grows, "s gtp is hydrolyzed. Protofilaments come together to form a barrel structure (microtubule) Triplets have an additional c ring with another additional 10 protofilaments.
