BP

GO:0006936

muscle contraction

A process in which force is generated within muscle tissue, resulting in a change in muscle geometry. Force generation involves a chemo-mechanical energy conversion step that is carried out by the actin/myosin complex activity, which generates force through ATP hydrolysis.

IBA|TAS

BP

GO:0007015

actin filament organization

A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of cytoskeletal structures comprising actin filaments. Includes processes that control the spatial distribution of actin filaments, such as organizing filaments into meshworks, bundles, or other structures, as by cross-linking.

IBA

BP

GO:0030239

myofibril assembly

Formation of myofibrils, the repeating units of striated muscle.

IBA

BP

GO:0030838

positive regulation of actin filament polymerization

Any process that activates or increases the frequency, rate or extent of actin polymerization.

IDA

BP

GO:0045010

actin nucleation

The initial step in the formation of an actin filament, in which actin monomers combine to form a new filament. Nucleation is slow relative to the subsequent addition of more monomers to extend the filament.

IDA

BP

GO:0051694

pointed-end actin filament capping

The binding of a protein or protein complex to the pointed (or minus) end of an actin filament, thus preventing the addition, exchange or removal of further actin subunits.

IEA

CC

GO:0005737

cytoplasm

All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.

IDA

CC

GO:0005829

cytosol

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.

TAS

CC

GO:0005865

striated muscle thin filament

Filaments formed of actin and associated proteins; attached to Z discs at either end of sarcomeres in myofibrils.

IBA

CC

GO:0005884

actin filament

A filamentous structure formed of a two-stranded helical polymer of the protein actin and associated proteins. Actin filaments are a major component of the contractile apparatus of skeletal muscle and the microfilaments of the cytoskeleton of eukaryotic cells. The filaments, comprising polymerized globular actin molecules, appear as flexible structures with a diameter of 5-9 nm. They are organized into a variety of linear bundles, two-dimensional networks, and three dimensional gels. In the cytoskeleton they are most highly concentrated in the cortex of the cell just beneath the plasma membrane.

ISS

CC

GO:0016020

membrane

A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.

TAS

CC

GO:0030016

myofibril

The contractile element of skeletal and cardiac muscle; a long, highly organized bundle of actin, myosin, and other proteins that contracts by a sliding filament mechanism.

IDA

CC

GO:0030017

sarcomere

The repeating unit of a myofibril in a muscle cell, composed of an array of overlapping thick and thin filaments between two adjacent Z discs.

ISS

MF

GO:0003779

actin binding

Interacting selectively and non-covalently with monomeric or multimeric forms of actin, including actin filaments.

IEA

MF

GO:0005523

tropomyosin binding

Interacting selectively and non-covalently with tropomyosin, a protein associated with actin filaments both in cytoplasm and, in association with troponin, in the thin filament of striated muscle.

IBA