β-actin (gene name ACTB) is one of six different actin isoforms which have been identified in humans. This is one of the two non-muscle cytoskeletal actins. Actins are highly conserved proteins that are involved in cell motility, structure and integrity. The β-actin gene is often stably and constitutively expressed at high levels in most tissues and cells. Proteins such as β-actin, involved in maintenance of basic cellular function, are often referred to as housekeeping proteins. Housekeeping proteins are frequently used as loading controls for western blots and protein normalization.