This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the transport of the sodium or lithium ions to allow salt tolerance. Is negatively modulated by SIS2/HAL3. ATP + H2O + Na(+)(in) = ADP + H(+) + Na(+)(out) + phosphate By sodium ions. Induction at low salt concentrations (0.3 M) is mediated by the high-osmolarity glycerol (HOG)-MAP kinase pathway, a system activated by non-specific osmotic stress, and by the protein kinase A pathway. At high salt concentrations (0.8 M) is mediated by the protein phosphatase calcineurin, which is specifically activated by sodium ions. Present with 688 molecules/cell in log phase SD medium. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IID subfamily.