β-Actin （gene name ACTB， a ubiquitous eukaryotic protein, is the major component of the cytoskeleton. At least six isoforms are known in mammals. Actins are highly conserved proteins that are involved in cell motility, structure and integrity. β-actin is a major constituent of the contractile apparatus, which is usually used as a loading control, for among others, the integrity of cells, protein degradation, in PCR and Western blotting. Its molecular weight is approximately 43 kDa.