This is the non-catalytic component of the active enzyme, which catalyzes the hydrolysis of ATP coupled with the exchange of Na(+) and K(+) ions across the plasma membrane. The beta subunit regulates, through assembly of alpha/beta heterodimers, the number of sodium pumps transported to the plasma membrane (PubMed:22328500). Plays a role in innate immunity by enhancing virus-triggered induction of interferons (IFNs) and interferon stimulated genes (ISGs). Mechanistically, enhances the ubiquitination of TRAF3 and TRAF6 as well as the phosphorylation of TAK1 and TBK1 (By similarity). Involved in cell adhesion and establishing epithelial cell polarity. The sodium/potassium-transporting ATPase is composed of a catalytic alpha subunit, an auxiliary non-catalytic beta subunit and an additional regulatory subunit. Interacts with catalytic subunit ATP12A (By similarity). Interacts with regulatory subunit FXYD1 (PubMed:21454534). Interacts with regulatory subunit FXYD3 (By similarity). Interacts with NKAIN1, NKAIN2 and NKAIN4 (By similarity). Interacts with MLC1. Part of a complex containing MLC1, TRPV4, AQP4 and HEPACAM. Interacts with KIRREL3 (By similarity). Interacts with OBSCN (via protein kinase domain 1) (By similarity). Interacts with TRAF3 and TRAF6 (By similarity). Colocalizes with OBSCN at the intercalated disk and sarcolemma in cardiomyocytes. Localizes in long striations at the level of Z and M lines. The C-terminal lobe folds into an immunoglobulin-like domain and mediates cell adhesion properties. Glutathionylated (By similarity). N-glycosylated (By similarity). Belongs to the X(+)/potassium ATPases subunit beta family.