The myofibril assembly process that results in the organization of muscle actomyosin into sarcomeres. The sarcomere is 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.

The process whose specific outcome is the progression of the skeletal muscle fiber over time, from its formation to the mature structure. Muscle fibers are formed by the maturation of myotubes. They can be classed as slow, intermediate/fast or fast.

A vesicle-mediated transport process that results in the engulfment of external particulate material by phagocytes and their delivery to the lysosome. The particles are initially contained within phagocytic vacuoles (phagosomes), which then fuse with primary lysosomes to effect digestion of the particles.

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of detection of, or exposure to, a hyperosmotic environment, i.e. an environment with a higher concentration of solutes than the organism or cell.

Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of deprivation of nourishment.

The process whose specific outcome is the progression of the sorocarp over time, from its formation to the mature structure. The process begins with the aggregation of individual cells and ends with the mature sorocarp. The sorocarp is a structure containing a spore-bearing sorus that sits on top of a stalk. An example of this process is found in Dictyostelium discoideum.

Any process involved in the controlled self-propelled movement of a cell that results in translocation of the cell from one place to another.

The assembly of actin filament bundles; actin filaments are on the same axis but may be oriented with the same or opposite polarities and may be packed with different levels of tightness.

The process in which two or more actin filaments are connected together by proteins that act as crosslinks between the filaments. The crosslinked filaments may be on the same or differing axes.

A contractile actin filament bundle that consists of short actin filaments with alternating polarity, cross-linked by alpha-actinin and possibly other actin bundling proteins, and with myosin present in a periodic distribution along the fiber.

A cell-cell adherens junction which forms a continuous belt near the apex of epithelial cells.

An occluding cell-cell junction that is composed of a branching network of sealing strands that completely encircles the apical end of each cell in an epithelial sheet; the outer leaflets of the two interacting plasma membranes are seen to be tightly apposed where sealing strands are present. Each sealing strand is composed of a long row of transmembrane adhesion proteins embedded in each of the two interacting plasma membranes.

Small region on the surface of a cell that anchors the cell to the extracellular matrix and that forms a point of termination of actin filaments.

The portion of the plasma membrane at the lateral side of the cell. In epithelial cells, lateral plasma membranes are on the sides of cells which lie at the interface of adjacent cells.

A thin sheetlike process extended by the leading edge of a migrating cell or extending cell process; contains a dense meshwork of actin filaments.

Electron-dense region associated with a smooth muscle contractile fiber.

The area of a motile cell closest to the direction of movement.

The outer membrane of a muscle cell, consisting of the plasma membrane, a covering basement membrane (about 100 nm thick and sometimes common to more than one fiber), and the associated loose network of collagen fibers.

The desmosomal part containing plakoglobins, plakophilins, the N-termini of desmoplakins, as well as the cytoplasmic tails of the desmosomal cadherins, which together attach the plaque to the plasma membrane.

The desmosomal part containing the C-termini of desmoplakins which interact with the keratin intermediate filaments, serving to tether the intermediate filaments to the plasma membrane.

An electron dense body which may contain granules.

An actin-rich cytoskeletal network located beneath the microvilli of the apical plasma membrane of polarized epithelial cells. In addition to actin filaments, the terminal web may contain actin-binding proteins, myosin motor proteins, and intermediate filaments. The terminal web can function as a contractile structure that influences the spatial distribution of microvilli as well as the development and morphogenesis of tissues containing polarized epithelial cells.

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

Extra-nucleolar nuclear domains usually visualized by confocal microscopy and fluorescent antibodies to specific proteins.

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.

The region of a cell that lies just beneath the plasma membrane and often, but not always, contains a network of actin filaments and associated proteins.

A structure lying external to one or more cells, which provides structural support, biochemical or biomechanical cues for cells or tissues.

A temporary protrusion or retractile process of a cell, associated with flowing movements of the protoplasm, and serving for locomotion and feeding.

The area of a motile cell closest to the direction of movement.

A cell projection that forms at the site of macropinocytosis, a form of endocytosis that results in the uptake of relatively large amounts of extracellular fluid. The macropinocytic cup membrane selectively excludes certain proteins, such as H36 or PM4C4 in Dictyostelium, and the underlying cytoskeleton is enriched in F-actin and coronin.