The role of ankyrin in shape and deformability change of human erythrocyte ghosts.
Human erythrocyte membranes (ghosts) from acid/citrate/dextrose preserved blood were digested with trypsin (protein/trypsin = 100:1) under hypotonic conditions and then analyzed by SDS-polyacrylamide gel electrophoresis. After digestion for about 20-30 s at 0 degree C, only ankyrin had disappeared and other bands including spectrin, actin, band 4.1 and band 3 remained intact. This observation was supported by electron micrographs showing that the horizontally disposed, filamentous structure was a little apart from the lipid bilayer and its components were not destroyed. In contrast to intact ghosts, treatment with chlorpromazine, or Mg-ATP did not induce shape change in these trypsin-treated ghosts. The number of transformable cells correlated closely with the amount of remaining ankyrin in the SDS-polyacrylamide gel electrophoresis pattern. Furthermore, the chlorpromazine- and Mg-ATP-induced decreases in viscosity of suspensions of erythrocyte ghosts were also prevented by trypsin treatment for 20-30 s at 0 degree C. These findings suggest that ankyrin plays an important role in the change in shape and deformability of erythrocyte ghosts. The molecular mechanism of drug-induced shape change and the role of undermembrane structure in regulating erythrocyte shape and deformability are discussed.
D017487:Ankyrins; D002746:Chlorpromazine / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000648:ultrastructure*; D006801:Humans; D008565:Membrane Proteins / Q000097:blood / Q000302:isolation & purification / Q000502:physiology*; D008854:Microscopy, Electron; D010446:Peptide Fragments / Q000032:analysis; D014357:Trypsin
D017487:Ankyrins; D008565:Membrane Proteins; D010446:Peptide Fragments; D014357:Trypsin; D002746:Chlorpromazine