C YTOSKELETON Frank Candre Tommy Palm Vidit Talati Varun Kumar Eric Yi

S TRUCTURE Microtubules (Tubulin Polymer) Microfilaments (Actin Filaments) Intermediate Filaments

F UNCTION 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

M ICROTUBULES 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

M ICROFILAMENTS 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)

I NTERMEDIATE F ILAMENTS 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

I NTERESTING L INKS Cytoskeleton Explanation Cytoskeleton Rap