Actin Cytoskeleton: structure, polymerization, and motor interactions

Apuntes

Cytoskeleton I Class 12 Cell Biology Prof. Lilian Spencer Cytoskeleton Cell culture colored with Coomassie blue Function of the Cytoskeleton Spatial and mechanicals: Change of form Movement organelles transportation Cellular division Interaction with the environment Filament System Microfilaments : - 2 Helical strands - Diameter 5 - 9 nm - Location behind Plasmatic M. Projections: Filopodia and Lamellipodia (locomotion) Intermediate filaments : - Cord-like fibers - D. 10 nm (Ex. Laminin) - They give strength and resistance (hair, nails, extensions of neurons) Microtubules : - Long, cylindrical and hollow - Formed by tubulin heterodimers - D. 25 nm - MTCO or Centrosome (extreme or end -) Direct intracellular transport, cilia and flagella Cytoskeleton and changes in cellular form Actin: - Monomer nucleated by ATP or ADP - Arrangement in 2 strands in the form of α-helix - F. Actin bind cross-linked with accessory proteins → give more strength to the filament. - Features 2 poles : +: if ΔG<0 addition → Polarization - : ΔG>0 lost → Depolarization Structure of Actin G monomer ATP Mg Two parallel strands of a helix Filament interact with: -Prot. Accesories (assembly) ↓ - Prot. Motor (moti...