BIOL 1090 Lecture Notes - Lecture 19: Axoneme, Tubulin, Cytoskeleton
9 Apr 2019
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Document Summary
Dynamic network of interconnected filaments and tubes that extend throughout the cytosol (and some organelles) of eukaryotes. 3: contractility and motility structural support spatial organization within the cell intracellular transport. Structural components of cytoskeleton: microtubules, largest cytoskeletal element (~25nm, polymer of proteins alpha tubulin and beta tubulin, 2 major types: Axonemal mt: highly organized, stable and part of structures (axoneme) involved in cell movement (e. g. cilia, flagella) Shrinkage can occur very rapidly at the plus end (termed catastrophe) Microtubule-organizing center (mtoc)=central site of mt assembly: microtubule associated proteins (maps) Mediate interactions with other cellular structures:often stabilize mts or stimulate assembly (e. g. vesicles/organelles) Powered by microfilament specific motor protein myosin: microfilaments are dynamic: the plus end assembles quickly while the minus and assembles slowly, nucleation: slow, elongation: fast (monomers add to both ends, polymerization/depolymerization and structure/organization: Regulated by actin-binding proteins: arp2/3 complex (starts polymerization at branch points) Filaments can be loose arrays/networks or tight bundles/cables.
