title: Stomatin modulates the activity of the Anion Exchanger 1 (AE1, SLC4A1).
abstract: Anion Exchanger 1 (AE1) and stomatin are integral proteins of the red blood cell (RBC) membrane. Erythroid and kidney AE1 play a major role in HCO3-and Cl-exchange. Stomatins down-regulate the activity of many channels and transporters. Biochemical studies suggested an interaction of erythroid AE1 with stomatin. Moreover, we previously reported normal AE1 expression level in stomatin-deficient RBCs. Here, the ability of stomatin to modulate AE1-dependent Cl-/HCO3-exchange was evaluated using stopped-flow methods. In HEK293 cells expressing recombinant AE1 and stomatin, the permeabilities associated with AE1 activity were 30% higher in cells overexpressing stomatin, compared to cells with only endogenous stomatin expression. Ghosts from stomatin-deficient RBCs and controls were resealed in the presence of pH- or chloride-sensitive fluorescent probes and submitted to inward HCO3-and outward Cl-gradients. From alkalinization rate constants, we deduced a 47% decreased permeability to HCO3-for stomatin-deficient patients. Similarly, kinetics of Cl-efflux, followed by the probe dequenching, revealed a significant 42% decrease in patients. In situ Proximity Ligation Assays confirmed an interaction of AE1 with stomatin, in both HEK recombinant cells and RBCs. Here we show that stomatin modulates the transport activity of AE1 through a direct protein-protein interaction.
authors.affiliation: Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Genetet
authors.affiliation: Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Desrames
authors.affiliation: Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France.
authors.forename: Youcef
authors.initials: Y
authors.lastname: Chouali
authors.affiliation: Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Ripoche
authors.affiliation: Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Lopez
authors.affiliation: Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, 75739 Paris Cedex 15, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mouro-Chanteloup
mesh_terms: D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism*; D001639:Bicarbonates / Q000378:metabolism; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D055786:Gene Knockout Techniques; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D001639:Bicarbonates; D002712:Chlorides; D008565:Membrane Proteins; C036860:STOM protein, human