The Na+/K+ ATPase pump is essential for:
Na+/K+ ATPase is a heterotetrameric P-type primary active pump that couples ATP hydrolysis to export of three Na+ and import of two K+ per catalytic cycle, maintaining steep ionic gradients of low intracellular Na+ around 12 mM and high K+ around 140 mM. These gradients generate a negative membrane potential and provide chemical potential stored as sodium motive force. Numerous secondary active transporters harness that force rather than ATP directly, including sodium-coupled amino acid transporters SNAT and B0AT systems in intestine and proximal tubule, as well as SGLT1 glucose cotransporters
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 11: Na+-coupled secondary active transport.