BY: MARC WERNER AND

ASHLEY GRAYDON

CYTOSKELETON FUNCTIONSKeeps organelles in anchored locationsEstablishes and supports the shape of the cellHelps transport materials within the cellAn arrangement of protein fibers found in all

eukaryotic cellsSeparates the chromosomes in mitosis and

meiosis

CYTOSKELETON FIBERSMicrotubules: Organizes the cell and moves

materials within the cellActin Filaments: Accountable for cellular

compressionIntermediate Filaments: Stabilizes the

framework of the cell

MICROTUBULESBuilt by the monomers of alpha and beta

tubulinFound in both animal and plant cellsStraight, hollow cylinder walls made up of 13

protofilamentsGrow at the end of each polymerized dimer There are two types of microtubule motors:

-Kinesins- move toward the positive end of the microtubule

-Dyneins- move toward the negative end of the microtubule

ACTIN FILAMENTSProtein Actin monomers polymerize to form

long thin fibersSmallest of the cytoskeletal filamentsProvides mechanical strength to the cellAnchors the centrosomes at opposite poles of the

cell during mitosisLinks transmembrane proteins to cytoplasmic

proteins (ex cell surface receptors)interact with myosin filaments in skeletal muscle

fibers to provide the force of muscular contraction

INTERMEDIATE FILAMENTSAre cytoplasmic fibersHave several types of intermediate filament:

-Keratins- found in the epithelial cells and also form hair and nails

-Lamins- form a lattice that stabilizes the inner membrane of the nuclear envelope

-Nuerofilaments- strengthen the long axons of neurons

-Vimentins- provide mechanical strength to the muscle and other cells

DISEASES CAUSED BY DEFECTIVE CYTOSKELETONS

Sickle Cell Aneamia- produces defective hemoglobin which alters the red blood cells into the shape of a sickle, the lattice locks into the shape of a sickle, which obstructs the microcirculation

Duchenne Muscular Dystrophy- Mutation in the dystophin gene disrupts the ability of the proteins to hold on to the cytoskeletal elements to the surface of the membrane