Beta-actin (PS1TP5-binding protein 1), also known as ACTB, PS1TP5BP1. Entrez Protein NP_001092. It is one of six different actin proteins. Actin, a ubiquitous eukaryotic protein, is the major component of the cytoskeleton.Actins are highly conserved proteins that are involved in various types of cell motility, structure, and integrity. Actin is ubiquitously expressed in all eukaryotic cells. This actin is a major constituent of the contractile apparatus and one of the two nonmuscle cytoskeletal actins.