actin

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actin

 [ak´tin]
a muscle protein localized in the I band of myofibrils; acting along with myosin particles, it is responsible for the contraction and relaxation of muscle fibers.

ac·tin

(ak'tin),
One of the protein components into which actomyosin can be split; it can exist in a fibrous form (F-actin) or a globular form (G-actin).

actin

/ac·tin/ (ak´tin) a muscle protein localized in the I band of the myofibrils; acting along with myosin, it is responsible for contraction and relaxation of muscle. It occurs in globular (G-actin) and fibrous (F-actin) forms.

actin

(ăk′tĭn)
n.
A protein that forms the microfilaments of the eukaryotic cytoskeleton and plays an important role in cell movement, shape, and internal organization. In muscle cells, it functions with myosin to produce contraction.

actin

a protein forming the thin filaments in muscle fibers that are pulled on by myosin cross-bridges to cause a muscle contraction. Some bacteria forms actin tails to use for motility. See also myosin.

Actin

One of two major muscle proteins—the other is myosin—which is an ATPase that binds to adenine nucleotides. In concert with myosin, actin is a filamentous protein responsible for muscle contraction, and has an active mechanicochemical role in cell function; it is divided into a 46-kD monomeric form, G-actin and a mature contractile form, F-actin, formed from G-actin polymers, capable of functioning in absence of myosin.

ac·tin

(ak'tin)
One of the protein components into which actomyosin can be split; it can exist in a fibrous form (F-actin) or a globular form (G-actin).

actin

A contractile protein in muscle, found in the thin filaments, to which the myosin cross-bridges bind. Actin filaments are also abundant inside all nucleated cells where they form the cytoskeleton, determining cell shape and, in the case of amoebic cells, cell movement. An actin contractile ring forms around the equator of a dividing cell at the end of MITOSIS and tightens so as to pinch the two daughter cells apart.

actin

a contractile protein found in the muscles of all animals from protozoa to vertebrates and in the MICROFILAMENTS of all cells. The energy for contraction is derived from ATP; See MYOSIN.
Figure 1: The autonomic nervous system. Actions on secretory functions (heart diagrams indicate release into the circulation). Sympathetic actions on the left and parasympathetic actions on the right. Solid arrows: stimulation (contraction or secretion); broken arrows: inhibition.

actin

globular protein molecule which readily links with others (with consumption of ATP) to form long, double-helical strands. Such actin filaments are found in a wide variety of animal and plant cells, as well as forming the structural core and main (but not only) component of the thin filaments in the myofibrils of all animal muscles. Actin is thus a protein of great evolutionary antiquity and vertebrate striated muscles are unusual only in having a very high content of it (80% of total protein), and in its highly ordered locations within the cells, where thin filaments alternate with thick filaments containing actin's partner protein myosin, to form the cross-striated pattern. See also muscle, muscle fibres; Figure 1.

actin (akˑ·tin),

n one of a pair of myofilaments involved in muscle contractions. See also myosin.

actin

a muscle protein localized in the I band of myofibrils; acting along with myosin particles, it is responsible for the contraction and relaxation of muscle.

actin F
assembly of actin G monomers into filaments.
actin filaments
smallest filamentous proteins involved in a static role in cell structure and a dynamic role in cell movement.
actin G
monomeric globular protein which assembles into actin filaments.
References in periodicals archive ?
Actin filaments are the tracks for myosin movement and their conformation affects myosin motility.
But when we tried to slide actin filaments in two adjacent sarcomeres toward centers of respective sarcomeres as it is described in the sliding filament theory, the Z disc that was common to both sarcomeres was not able to move toward the center of either sarcomere (Figure 2).
Formins are large multi-domain proteins required for the assembly of straight actin filaments found in the cytokinetic contractile ring, yeast actin cables, adherens junctions between epithelial cells and filopodial protrusions (Chang et al.
5): (1) there were were fewer cells in mitosis in the MCF7 cells treated with actein at 20[micro]g/ml for 48 h, and (2) the distribution of actin filaments was altered after treatment with actein in both the MCF7 and MDA-MB-453 cells.
These filaments, which ran parallel to the cell edge, could be the enhanced actin filaments, and together with the accumulated progeny virus particles, could have caused the bulky, puffy-cell periphery.
Dihydrocytochalasin B causes depolymerization of actin filaments by capping the fast growing end of the flaments.
Actin filaments labeled with rhodamine--phalloidin were allowed to move on Physarum or scallop myosin fixed to a nitro cellulose-coated glass surface.
Objective: The cell cortex is a highly dynamic layer of crosslinked actin filaments and myosin molecular motors beneath the cell membrane.
The convergent extension of notochord cells is dependent on actin filaments, and the movement is regulated by molecules similar to those involved in the formation of the planar cell polarity (PCP) of epithelial cells, such as Prickle (Tree et al.
David Williams, who earned his doctorate at the UW while conducting the research, said that the predominant thinking of the last 50 years is that 100 percent of the muscle force comes from changes as muscles shorten and myosin and actin filaments overlap.
Using a technique to make a pattern of active myosin molecules on a surface, they showed how cargo -- they used small beads -- could be attached to actin filaments and moved from one part of the surface to another.
2+], gelsolin severs and caps polymeric actin filaments (F-actin) (21): after binding of domain G1 and partly domain G2 to the actin filament (F-actin), gelsolin rapidly severs F-actin and then remains bound to the barbed end of one of the newly formed filaments, forming a stable cap, thus inhibiting addition of further monomers.