Actincontaining

Actincontaining is an adjective used in cell and molecular biology to describe molecules, complexes, structures, or compartments that include actin as a constituent. Actin is a highly conserved, ATP-dependent globular protein that polymerizes into helical filaments forming microfilaments, essential for shaping the cytoskeleton, enabling movement, division, and intracellular trafficking.

In eukaryotic cells, actincontaining structures include microfilaments and higher-order networks such as lamellipodia and filopodia, the contractile ring of cytokinesis, and stress fibers. These filaments interact with actin-binding proteins (e.g., profilin, cofilin, Arp2/3, formins) to regulate polymerization, organization, and turnover.

Actincontaining complexes include actin and binding partners, such as myosin motors; vesicle-associated actin structures; actin-based motility in intracellular pathogens like Listeria monocytogenes, which form actin comet tails to move.

Methodologies used to study actincontaining structures include detection by phalloidin staining; visualization by fluorescence and confocal microscopy; and genetic or pharmacological disruption of actin polymerization to assess effects on the structures.

In bacteria, actin-like proteins (MreB, ParM) share functional similarity but are distinct from eukaryotic actin; the term actincontaining is typically reserved for true actin-containing assemblies in eukaryotes.