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The Rh complex exports ammonium from human red blood cells
Author(s) -
Hemker Mirte B.,
Cheroutre Goedele,
Van Zwieten Rob,
Maaskantvan Wijk Petra A.,
Roos Dirk,
Loos Johannes A.,
Van Der Schoot C. Ellen,
Von Dem Borne Albert E. G. Kr.
Publication year - 2003
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2003.04425.x
Subject(s) - ammonium , chemistry , intracellular , ammonium sulfate , biochemistry , incubation , chromatography , organic chemistry
Summary. The Rh blood group system represents a major immunodominant protein complex on red blood cells (RBC). Recently, the Rh homologues RhAG and RhCG were shown to promote ammonium ion transport in yeast. In this study, we showed that also in RBC the human Rh complex functions as an exporter of ammonium ions. We measured ammonium import during the incubation of RBC in a solution containing a radiolabelled analogue of NH 4 Cl ( 14 C‐methyl‐NH 3 Cl). Rh null cells of the regulator type (expressing no Rh complex proteins) accumulated significantly higher levels ( P = 0·05) of radiolabelled methyl‐ammonium ions than normal RBC, at room temperature. Rh null cells of the amorph type (expressing limited amounts of Rh complex proteins) accumulated an intermediate amount of methyl‐ammonium ions. To show that decreased ammonium export contributes to its accumulation, the release of intracellular methyl‐ammonium from the cells was measured over time. In 30 s, normal RBC released 87% of the intracellular methyl‐ammonium ions, whereas Rh null cells of the regulator type released only 46%. We conclude that the Rh complex is involved in the export of ammonium from RBC.