actin filament

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Related to actin filament: Intermediate filament, myosin filament


1. a delicate fiber or thread.
2. in an x-ray tube, the wire (cathode) that makes electrons available for interaction with the anode when it is heated to incandescence to form an electron cloud.
actin filament one of the thin contractile filaments in a myofibril, composed mainly of actin; each actin filament is surrounded by three myosin filaments.
myosin filament one of the thick contractile filaments in a myofibril, composed mainly of myosin; each myosin filament is surrounded by six actin filaments.

ac·tin fil·a·ment

one of the contractile elements in muscular fibers and other cells; in skeletal muscle, the actin filaments are about 7.5 nm wide and 1 mcm long, and attach to the transverse Z filaments.
Synonym(s): thin filament

Actin Filament

A long, slender chain of G-actin which transmits tension in muscles, participates in cell protrusion, and acts as scaffolding for binding dozens of different molecules. Actin filaments (AFs) can withstand molecular forces, but are highly sensitive to gelsolin.
Gelsolin cleaves AFs with almost surgical precision; gelsolin-actin cleavage is strictly regulated; micromolar concentrations of Ca2+ or a low pH cause gelsolin to sever; certain phosphoinositides inhibit severing, and may release gelsolin and allow AF growth. By EM, AFs are attached at one end to the Z bands and at the other interdigitate with myosin filaments.

ac·tin fil·a·ment

(ak'tin fil'ă-mĕnt)
One of the contractile elements in muscular fibers and other cells; in skeletal muscle, the actin filaments are about 5 nm wide and 100 mcm long; they attach to the transverse Z filaments.
References in periodicals archive ?
40)-(42) The geometric arrangement of the actin filament interaction with myosin molecules that are attached to a large scanning probe affects the shape of the potential.
Actin filaments are also required for meiotic spindle rotation in Xenopus and sheep oocytes.
Dihydrocytochalasin B causes depolymerization of actin filaments by capping the fast growing end of the flaments.
This section describes Ca inhibition caused by modulating actin filaments in a [Ca.
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.
The first evidence for the polar nature of actin filament was the arrowhead pattern revealed by adding myosin heads to actin filaments.
Myosin V is thought to bind a vesicle at its tail and transport the vesicle by moving processively, step by step along an actin filament without dissociation.
The long, needlelike sperm from the Friday Harbor population possessed a deep, narrow nuclear fossa with a long rod of actin filaments that stained brightly in both intact and acrosome-reacted sperm (see Fig.
2+] sensitive, 41,000-dalton protein which reversibly blocks the "barbed" ends of actin filaments but does not sever them.
1972), and cortical spindle positioning involves actin filaments and formin-2 rather than astral microtubules (Leader et al.
The hypothesis holds that myosin molecules, arranged in long filaments, latch on to binding sites along actin filaments and perform a "power stroke" that pulls the actin filament past the myosin filament.
Then another bond is made a little farther down the actin filament and the process is repeated.