BIOL 1090 Lecture Notes - Lecture 22: Dynein, Kinesin, Cytoskeleton
Document Summary
Dynein and kinesin (motor protein complexes) power intracellular transport. Burn atp to move along a track on the microtubules. Attached to the microtubules through a motor domain head. Stable fibrous proteins contain central theta-helical domain: epithelial cells (keratins), neurons (neurofilaments), and nucleus of all cells (lamins) They are not polar but are made of polar molecules: monomer is polar, dimer is 2 monomer with polar ends, tetramer will have antiparallel dimers making it nonpolar. Functions: maintenance of cell shape, cell movement, cytokinesis, muscle contraction, vesicle transport. F-actin microfilament: g-actin monomers have polar structure, monomers are incorporated into the filament in the same orientation, f-actin filament is polar (plus and minus end, has atp binding clefts, assembly. Slow nucleation (g-actin dimers trimmers short filaments) Fast elongation monomers are added to both ends (more monomers on + end: filaments can be loose arrays/networks or tight bundles/cables, regulated by actin-binding proteins, profilin acts to break down monomer polymerizing just like cofilin.
