Functions of Actin - anchor the cytoskeleton to areas of...

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Functions of Actin Cell crawling depends on actin The formation of filopodia and lamellipodia both depend upon actin polymerization. lamellipodia- thin, sheet-like extensions of the plasma membrane filopodia-thin, stiff protrusions of the plasma membrane Both are exploratory, motile structures that form and retract with great speed. Both are generated by rapid local growth of actin filaments, which are nucleated at the plasma membrane and push out the membrane without tearing. In addition, most cells have specialized regions of the plasma membrane that form contacts with adjacent cells, tissue components, or other substrates. These regions also serve as attachment sites for bundles of actin filaments that
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Unformatted text preview: anchor the cytoskeleton to areas of cell contact. The sites of attachment - focal adhesions- also serve as attachment sites for large bundles of actin filaments that are termed stress fibers. Stress fibers- are contractile bundles of actin filaments cross-linked by alpha-actinin. These bundles anchor the cell and exert tension against the subsratum. They are attached to the plasma membrane at focal adhesions via interactions with integrin. The actin cytoskeleton is similarly anchored to regions of cell-cell contact called adherins junctions. This attachment is mediated by a family of proteins known as adherins. ACTIN ALSO PLAYS A MAJOR ROLE IN MUSCLE CONTRACTION...
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This document was uploaded on 11/03/2011 for the course BIOLOGY MCB2010 at Broward College.

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