AskDefine | Define actin

Dictionary Definition

actin n : one of the proteins into which actomyosin can be split; can exist in either a globular or a fibrous form

User Contributed Dictionary



  1. A globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament).

See also


Extensive Definition

Actin is a globular, roughly 42-kDa protein found in all eukaryotic cells (except for nematode sperm) where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans. It is the monomeric subunit of microfilaments, one of the three major components of the cytoskeleton, and of thin filaments, which are part of the contractile apparatus in muscle cells. Thus, actin participates in many important cellular functions, including muscle contraction, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the establishment and maintenance of cell junctions and cell shape.

Formation of thin filament



actin in Bulgarian: Актин
actin in Czech: Aktin
actin in Danish: Actin
actin in German: Aktin
actin in Estonian: Aktiin
actin in Spanish: Actina
actin in French: Actine
actin in Galician: Actina
actin in Italian: Actina
actin in Hebrew: אקטין
actin in Macedonian: Актин
actin in Dutch: Actine
actin in Japanese: アクチン
actin in Polish: Aktyna
actin in Portuguese: Actina
actin in Romanian: Actină
actin in Russian: Актин
actin in Serbian: Актински филаменти
actin in Finnish: Aktiini
actin in Swedish: Aktin
actin in Tagalog: Actin
actin in Vietnamese: Sợi actin
actin in Turkish: Aktin
actin in Ukrainian: Актин
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