Editing Cytoskeleton (section)

===Microfilaments===
{{main|Microfilament}}
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| image1 = Microfilament Structure.svg
| caption1 = Structure of a [[microfilament]]
| image2 = MEF microfilaments.jpg
| caption2 = Actin cytoskeleton of [[mus musculus|mouse]] [[embryo]] [[fibroblast]]s, stained with [[phalloidin]]
}}

Microfilaments, also known as actin filaments, are composed of linear polymers of [[Actin#G-Actin|G-actin]] proteins, and generate force when the growing (plus) end of the filament pushes against a barrier, such as the cell membrane. They also act as tracks for the movement of [[myosin]] molecules that affix to the microfilament and "walk" along them. In general, the major component or protein of microfilaments are actin. The G-actin monomer combines to form a polymer which continues to form the microfilament (actin filament). These subunits then assemble into two chains that intertwine into what are called [[Actin#F-Actin|F-actin]] chains.<ref name="Cooper 2000">{{Cite journal|last=Cooper|first=Geoffrey M.|date=2000|title=Structure and Organization of Actin Filaments|url=https://www.ncbi.nlm.nih.gov/books/NBK9908/|journal=The Cell: A Molecular Approach. 2nd Edition|language=en|url-status=live|archive-url=https://web.archive.org/web/20180502014625/https://www.ncbi.nlm.nih.gov/books/NBK9908/|archive-date=2018-05-02}}</ref> Myosin motoring along F-actin filaments generates contractile forces in so-called actomyosin fibers, both in muscle as well as most non-muscle cell types.<ref name=gunning>{{cite journal | vauthors = Gunning PW, Ghoshdastider U, Whitaker S, Popp D, Robinson RC | title = The evolution of compositionally and functionally distinct actin filaments | journal = Journal of Cell Science | volume = 128 | issue = 11 | pages = 2009–19 | date = June 2015 | pmid = 25788699 | doi = 10.1242/jcs.165563 | doi-access = free }}</ref> Actin structures are controlled by the [[Rho family]] of small GTP-binding proteins such as Rho itself for contractile acto-myosin filaments ("stress fibers"), Rac for lamellipodia and Cdc42 for filopodia.

Functions include:
* [[Muscle contraction]]
* Cell movement
* Intracellular transport/trafficking
* Maintenance of [[Eukaryote|eukaryotic]] cell shape
* [[Cytokinesis]]
* Cytoplasmic streaming<ref name="Cooper 2000"/>