Cell Surface Expression of a Specific Antigenic Site on the Catalytic Subunit of (Na+ + K+)-ATPase

Abstract

Structural localization of a peptide region, KRQPRNPKTDKLVNE, in the catalytic subunit of (Na+ + K+)-ATPase was investigated using a specific antibody directed against this peptide in cultured African green monkey kidney CV-1 cells. Immunofluorescence staining of frozen cell sections shows that an anti-KRQPRNPKTDKLVNE antibody (SSA95) interacts with its antigenic site and binds to the extracellular side of the cell membrane. Indirect immunofluorescence and flow cytometric analyses confirmed the presence of this epitope on intact cell surfaces. These results suggest that the KRQPRNPKTDKLVNE region of the (Na+ + K+)-ATPase is expressed on the cellular membrane surface.