1. Cytoskeleton Frank Candre Tommy Palm ViditTalati Varun Kumar Eric Yi

2. Structure • Microtubules (Tubulin Polymer) • Microfilaments (Actin Filaments) • Intermediate Filaments

3. Function • Give mechanical support to the cell and maintain its shape • Important in animal cells because they lack cell walls • Provides anchorage for many organelles and even cytosolic enzyme molecules • Interaction between cytoskeleton with motor proteins can assist in cell motility (cilia and flagella) • Manipulates the plasma membrane in a way that forms food vacuoles or other phagocytic vesicles • Cytoskeletal transmission of naturally occurring mechanical signals may help regulate and coordinate the cell’s response

4. Microtubules • Structure: Hollow tubes; wall consists of 13 columns of tubulin molecules • Diameter: 25nm with 15-nm lumen • Protein Subunits: Tubulin, a dimer consisting of alpha-tubulin and beta-tubulin • Main functions: maintenance of cell shape (compression resistant “girders”), cell motility (movement), chromosome movements in cell division, organelle movements

5. Microfilaments • Structure: Two intertwined strands of actin proteins, each a polymer of actin subunits • Diameter: 7 nm • Protein Subunits: Actin • Main Functions: Maintenance of cell shape (tension-bearing elements), changes in cell shape, muscle contraction, cytoplasmic streaming, cell motility (as in pseudopodia), cell division (cleavage furrow formation)

6. Intermediate Filaments • Structure: Fibrous proteins supercoiled into thicker cables • Diameter: 8-12 nm • Protein Subunits: One of several different proteins in the keratin family, depending on cell type • Main Functions: Maintenance of cell shapes (tension-bearing elements), anchorage of nucleus and certain other organelles, formation of nuclear lamina

7. Interesting Links • Cytoskeleton Explanation • Cytoskeleton Rap