actin

actin, a protein abundantly present in many cells, especially muscle cells, that significantly contributes to the cell's structure and motility. Actin can very quickly assemble into long polymer rods called microfilaments. These microfilaments have a variety of roles—they form part of the cell's cytoskeleton, they interact with myosin to permit movement of the cell, and they pinch the cell into two during cell division. In muscle contraction, filaments of actin and myosin alternately unlink and chemically link in a sliding action. The energy for this reaction is supplied by adenosine triphosphate.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on actin from Fact Monster:

  • myosin - myosin myosin , one of the two major protein constituents responsible for contraction of muscle. In ...
  • muscle: Muscle Contraction - Muscle Contraction Skeletal muscles are attached (with some exceptions, such as the muscles of the ...
  • skin cancer: Basal and Squamous Cell Carcinomas - Basal and Squamous Cell Carcinomas Basal and squamous cell carcinomas are the most common types of ...
  • protein: Types of Proteins - Types of Proteins A protein molecule that consists of but a single polypeptide chain is said to be ...
  • sunburn - sunburn sunburn, inflammation of the skin caused by actinic rays from the sun or artificial ...

See more Encyclopedia articles on: Biochemistry