What is the role of microfilaments in cytokinesis?

Chapter 3: Cell Structure and Function from the Holt McDougal Biology Textbook, many thanks to Holt McDougal!

The cytoskeleton, a network of proteins that is dynamically rearranged to suit the demands of each eukaryotic cell, is composed of small protein subunits that crisscross the entire cell in the form of long threads called fibers. There are three primary types of fibers that comprise the cytoskeleton, which is responsible for a variety of functions.

• When cells divide, microtubules form fibers that pull half of the DNA into each new cell. Microtubules are long, hollow tubes that give cells their shape and function as "tracks" for the movement of organelles.

• A cell's strength comes from intermediate filaments, which are slightly smaller than microtubules.

• The smallest of the three, called microfilaments, are minuscule threads that facilitate cell division and motility. They are particularly significant in muscle cells, where they aid in the contraction and relaxation of the muscle.

Actin-based microfilaments are essential for cytokinesis because, during cell division, they form a contractile ring at the equator of the cell, which pinches the cell membrane inward and eventually separates the two daughter cells, ensuring that the contents of the newly formed cells are distributed equally.