[Gk. aktis, a ray] A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells.

a continually shrinking and expanding protein which exists in conjunction with myosin inside muscular fibers to negotiate muscular contractions.

Actin is a protein that along with myosin (another protein) forms myofibrils which are muscle fibers that control muscular contractions. Strands of actin and myosin overlap to form myofibrils which ar [..]

A type of protein that makes up the thick filaments in a myofibril.

  One of the two contractile proteins in muscle (the other being myosin). Actin is also found in the microfilaments that form part of the cytoskeleton of all cells.

Cytoskeletal 43 kD protein forming the backbone of the cytoplasmic microfilament system and the thin filament system of muscle sacomeres. In humans, there are distinct muscle (4 alpha-skeletal, alpha-cardiac, alpha-smooth, gamma-smooth) and non-muscle (2 cytoskeletal beta-, gamma-) actin isoforms. Exists as globular actin monomer (G-actin) and micr [..]

A protein that, along with myosin, mediates the contraction of muscle fibers. See Figure 11.7.

A protein found in combination with myosin in muscle and also found as filaments constituting an important part of the cytoskeleton in many eukaryotic cells.

A very common protein that forms filaments. It provides a kind of cellular “skeleton” in the cytoplasm of all cells, and also plays a major role in muscle contraction. It has been found to be present [..]

A globular protein found in cells; it is the monomer and fundamental unit of two types of filaments – microfilaments (component parts of the cytoskeleton) and thin filaments (part of the contractile apparatus in muscle cells). Actin participates in many important cellular processes, including muscle contraction, cell motility, cell division and cyt [..]

One of the main proteins involved in muscle contraction. Actin binds with myosin, and is then pulled by it to cause muscle to contract. 

Myofibrillar protein and main component of the I-band or thin filament of the sarcomere. F-actin is made up of a series of the g-actin molecules that form a helical strand known as a thin filament.

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

One of the proteins that allows cells to move and muscles to contract.

Abundant structural protein in eukaryotic cells that interacts with many other proteins. The monomeric globular form (G actin) polymerizes to form actin filaments (F actin). In muscle cells, F actin i [..]

Filamentous Proteins that are the main constituent of the thin filaments of Muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each su [..]

The major component of thin muscle filaments. Together with the motor protein myosin, which forms thick filaments, it is arranged into actomyosin myofibrils. These fibrils comprise the mechanism of muscle contraction.

A globular protein found in all plant and animal cells that can polymerize into microfilaments. The globular form is called G-actin, the polymerized form F-actin. Actin is important in organelle movem [..]

<cell biology> A filamentous proteins (42 kD) involved in muscle contraction in both smooth and striated muscle and also serves as an important structural molecule for the cytoskeleton of many eukaryotic cells. It is the main constituent of the thin filaments of muscle fibres. The filaments (known also as filamentous or f-actin) can be dissoc [..]

A protein that forms fibers that make up part of the cytoskeletons.

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