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Abstract

This review summarizes evidence that Na⁺/K⁺-ATPase β-sub-units have two essential functions. First, β-subunits constitute an indispensable part of Na⁺/K⁺-ATPase, the minimum functional unit of which is an αβ-heterodimer, by stabilizing the correct folding of the catalytic α-sbunit. The various β-isoforms confer different K⁺ affinities to the mature enzyme. Second, β₂-subunits are involved in cell-cell interactions. To account for both functions, we discuss the possibility that β-subunits can serve as recognition molecules which transmit extracellular information onto the α-subunit or by themselves interact with receptors of neighboring cells.