Beta-actin

Beta-actin, or Actin beta is one of six different actin isoforms which have been identified in humans. This is one of the two nonmuscle cytoskeletal actins. Actins are highly conserved proteins that are involved in cell motility, structure and integrity. Alpha actins are a major constituent of the contractile apparatus.

Interactions

Actin beta has been shown to interact with SPTBN2. In addition, RNA-binding protein Sam68 was found to interact with the mRNA encoding actin beta, which regulates the synaptic formation of the dendritic spines with its cytoskeletal components.
Actin beta has been shown to activate eNOS, thereby increasing NO production. An eight-amino acid motif in eNOS has been shown to mediate the interaction between actin and eNOS.

Clinical relevance

Recurrent mutations in this gene have been associated to cases of diffuse large B-cell lymphoma. De novo gain-of-function mutations in this gene is associated with Baraitser-Winter syndrome.

Applications

Actin beta is often used in Western blotting as a loading control, to normalize total protein amounts and check for eventual protein degradation in the samples. Its transcript is also commonly used as a housekeeping gene standard in qPCR. Its molecular weight is approximately 42 kDa.