INCREASED POTASSIUM-TRANSPORT AND OUABAIN BINDING IN HUMAN RHNULL RED BLOOD-CELLS
- 1 January 1976
- journal article
- research article
- Vol. 48 (3) , 457-468
Abstract
K+ influx and 3H-ouabain binding were studied in human Rhnull cells and compared with normal Rh(D) red cells. The Rhnull cells were normal in size, cation and water content, indicating no significant increase in cell volume as occurs in young human red cells. The ouabain-insensitive K+ permeability, and the ouabain-sensitive active K+ transport, were increased 1.6-1.8- and 1.4-1.5-fold, respectively, above the values found in Rh(D) control cells. The Na+K+ ATPase activity of membranes from Rhnull cells was also higher than from Rh(D) cells. Binding studies with 3H-ouabain revealed that at 100% K+ pump inhibition, Rhnull cells bound 670 and Rh(D) cells 450-500 ouabain molecules per cell. Since the rate of ouabain binding was identical in Rhnull and Rh(D) control cells, the Rhnull cell had about 35%-45% more cation pumps than the Rh(D) cell. These additional pumps in Rhnull cells appeared indistinguishable from those in control cells. Anti-D or the serum from the Rhnull individual did not alter cation permeability in Rh(D) red cells. The Rhnull cell, known for its hematologic malfunction, was apparently not a young or prematurely released red cell, but had a pleiotropic membrane defect which also affected the passive and active cation transport system on the molecular level. These findings preclude a structural identity of the Rh antigen with the molecules composing the Na+K+ pump system.This publication has 5 references indexed in Scilit:
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