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Definition

noun, plural: microfilaments

A thin, helical, single-stranded filament of the cytoskeleton found in the cytoplasm of eukaryotic cells, composed of actin subunits, and functions primarily in maintaining the structural integrity of a cell and cell movements.

Supplement

Additionally, the microfilament:

• provides mechanical support for the cell or maintain structural integrity of the cell by forming a Band just beneath the cell membrane
• participates in certain cell junctions; link transmembrane proteins (e.g., cell surface receptors) to cytoplasmic proteins
• anchors the centrosomes at opposite poles of the cell during mitosis; aids in the contraction of the cell during cytokinesis
• generates cytoplasmic streaming (i.e. Intracellular movement, or the flowing of cytoplasm within cells)
• enables cell locomotion(through lamellipodia, filopodia, or pseudopodia)
• interacts with myosin ("thick") filaments in skeletal muscle fibers to provide the force of muscular contraction.

Word origin: Gk: comb. form repr. mīkrós, small + NL fīlāmentum, equiv. to LL fīlā(re), to wind thread, spin.

Related forms: microfilamentous (adjective).