Evidence that the red cell skeleton protein 4.2 interacts with the Rh membrane complex member CD47.
Rh(null) red cells are characteristically stomato-spherocytic. This and other evidence suggest that the Rh complex represents a major attachment site between the membrane lipid bilayer and the erythroid skeleton. As an attempt to identify the linking protein(s) between the red cell skeleton and the Rh complex, we analyzed the expression of Rh, RhAG, CD47, LW, and glycophorin B proteins in red cells from patients with hereditary spherocytosis associated with complete protein 4.2 deficiency but normal band 3 (4.2(-)HS). Flow cytometric and immunoblotting analysis revealed a severe reduction of CD47 (up to 80%) and a slower mobility of RhAG on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, possibly reflecting an overglycosylation state. Unexpectedly, 4.2(-/-) mice, which are anemic, displayed a normal red cell expression of CD47 and RhAG. These results suggest that human protein 4.2, through interaction with CD47, is involved in the skeleton linkage and/or membrane translocation of the Rh complex. However, these potential role(s) of protein 4.2 might be not conserved across species. Finally, the absence or low expression of red cell CD47 in CD47(-/-) mice and in some humans carrying RHCE gene variants (D--, D., and R(N)), respectively, had no detectable effect on protein 4.2 and RhAG expression. Since these cells are morphologically normal with no sign of hemolysis, it is assumed that CD47 deficiency per se is not responsible for the cell shape abnormalities and for the compensated hemolytic anemia typical of 4.2(-) and Rh(null) red cells.
Mouro-Chanteloup
Isabelle
I
Institut National de la Santé et de la Recherche Médicale (INSERM) U76, Institut National de la Transfusion Sanguine, Paris, France.
Delaunay
Jean
J
Gane
Pierre
P
Nicolas
Virginie
V
Johansen
Mette
M
Brown
Eric J
EJ
Peters
Luanne L
LL
Van Kim
Caroline Le
CL
Cartron
Jean Pierre
JP
Colin
Yves
Y
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism*; D051928:CD47 Antigen; D002352:Carrier Proteins / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004910:Erythrocyte Membrane / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D011485:Protein Binding; D012204:Rh-Hr Blood-Group System; D013103:Spherocytosis, Hereditary / Q000235:genetics / Q000378:metabolism
D015703:Antigens, CD; D001798:Blood Proteins; D051928:CD47 Antigen; C497894:CD47 protein, human; D002352:Carrier Proteins; C497895:Cd47 protein, mouse; D003598:Cytoskeletal Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C498523:RHAG protein, human; D012204:Rh-Hr Blood-Group System; C401210:Rhag protein, mouse; C026410:Rho(D) antigen; C044791:erythrocyte membrane band 4.2 protein