The Actin protein, a component of the eukaryotic cytoskeleton, is highly conserved between multiple species. Actin is a globular protein of approximately 42kDa. Levels of the Actin protein may vary between different cell types, but are consistent within a given cell type. For this reason, Actin protein levels are often considered a 'house-keeper', an internal control for protein loading.
The actin network represents an essential component of the cell cytoskeleton, which is made up of microfilaments composed of linear assemblies of actin molecules. Actin assembly is known to be important for the remodeling of cell shape during cell motility, cell division and morphogenesis. The biological functions of actin occur in concert with a large number of Actin binding proteins, including cofilin, actin depolymerization factor (ADF), myosins, and many more.
Actin molecules accumulate as Hirano bodies, in neurons of patients with Alzheimer's disease, Creutzfeldt-Jakob disease, and other neurodegenerative diseases. Hirano bodies are intracellular aggregates of actin and actin-associated proteins.