title: The human Kell blood group binds the erythroid 4.1R protein: new insights into the 4.1R-dependent red cell membrane complex.
abstract: Protein 4.1R plays an important role in maintaining the mechanical properties of the erythrocyte membrane. We analysed the expression of Kell blood group protein in erythrocytes from a patient with hereditary elliptocytosis associated with complete 4.1R deficiency (4.1(-) HE). Flow cytometry and Western blot analyses revealed a severe reduction of Kell. In vitro pull down and co-immunoprecipitation experiments from erythrocyte membranes showed a direct interaction between Kell and 4.1R. Using different recombinant domains of 4.1R and the cytoplasmic domain of Kell, we demonstrated that the R(46) R motif in the juxta-membrane region of Kell binds to lobe B of the 4.1R FERM domain. We also observed that 4.1R deficiency is associated with a reduction of XK and DARC (also termed ACKR1) proteins, the absence of the glycosylated form of the urea transporter B and a slight decrease of band 3. The functional alteration of the 4.1(-) HE erythrocyte membranes was also determined by measuring various transport activities. We documented a slower rate of HCO3 (-) /Cl(-) exchange, but normal water and ammonia transport across erythrocyte membrane in the absence of 4.1. These findings provide novel insights into the structural organization of blood group antigen proteins into the 4.1R complex of the human red cell membrane.
authors.affiliation: Institut National de la Transfusion Sanguine, Paris, France.|Inserm, UMR_S1134, Paris, France.|Université Paris Diderot, Sorbonne Paris Cité, Paris, France.|Laboratory of Excellence GR-Ex, New York, NY, USA.
authors.forename: Slim
authors.initials: S
authors.lastname: Azouzi
authors.affiliation: Institut National de la Transfusion Sanguine, Paris, France.|Inserm, UMR_S1134, Paris, France.|Université Paris Diderot, Sorbonne Paris Cité, Paris, France.|Laboratory of Excellence GR-Ex, New York, NY, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Collec
authors.affiliation: New York Blood Center, New York, NY, USA.
authors.forename: Narla
authors.initials: N
authors.lastname: Mohandas
authors.affiliation: New York Blood Center, New York, NY, USA.
authors.forename: Xiuli
authors.initials: X
authors.lastname: An
authors.affiliation: Institut National de la Transfusion Sanguine, Paris, France.|Inserm, UMR_S1134, Paris, France.|Université Paris Diderot, Sorbonne Paris Cité, Paris, France.|Laboratory of Excellence GR-Ex, New York, NY, USA.
authors.forename: Yves
authors.initials: Y
authors.lastname: Colin
authors.affiliation: Institut National de la Transfusion Sanguine, Paris, France.|Inserm, UMR_S1134, Paris, France.|Université Paris Diderot, Sorbonne Paris Cité, Paris, France.|Laboratory of Excellence GR-Ex, New York, NY, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Le Van Kim
mesh_terms: D000293:Adolescent; D000906:Antibodies / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000378:metabolism*; D004375:Duffy Blood-Group System / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006801:Humans; D007626:Kell Blood-Group System / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D011956:Receptors, Cell Surface / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: C473745:ACKR1 protein, human; D000906:Antibodies; D003598:Cytoskeletal Proteins; D004375:Duffy Blood-Group System; D007626:Kell Blood-Group System; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C028841:erythrocyte membrane band 4.1 protein
keywords: 4.1R; Kell protein; blood group antigens; erythrocyte membrane; macromolecular complex