• Microfilaments (aka actin filaments) are thin solid rods.
--> they are built from molecules of actin, a gobular protein.
• A 3D network formed by microfilaments just inside the plasma membrane (cortical microfilaments) helps support the cell's shape.
• This network gives the outer cytoplasmic layer of a cell, called the cortex, the semisolid consistency of gel, in contrast with the more fluid state of the interior cytoplasm.
• Thousands of actin filaments and thicker filaments made of a protein called myosin interact to cause contraction of muscle cells.
• The cell crawls along a surface by extending cellular extensions called pseudopodia.
• in plant cells, actin-protein interactions contribute to cytoplasmic streaming, a circular flow of cytoplasm within cells.