Dynamic association of band 3 with triton shells in human erythrocyte ghosts.
To test a possibility that free band 3 and ankyrin-linked band 3 are exchanged in situ, band 3 was labeled with 125I, using intact red blood cells and lactoperoxidase. The cytoplasmic surface of this labeled band 3 was considered to be intact. When Triton shells were incubated with Triton supernatants prepared from 125I-labeled intact erythrocytes at 37 degrees C in the presence of Mg-ATP under isotonic conditions, the incorporation of free 125I-labeled band 3 to shells was observed. This incorporation was affected by the presence of Triton X-100 in the incubation mixture, and significantly decreased when the content of Triton X-100 was less than 0.04% (v/v). On the other hand, ankyrin-linked 125I-labeled band 3 was released when shells prepared from 125I-labeled intact erythrocytes were incubated with the Triton supernatants at 37 degrees C under the same condition as when free 125I-labeled band 3 incorporation was observed. These results strongly suggest that free and ankyrin-linked band 3 exchanged with each other in the presence of Triton X-100. A water-soluble 43 kDa fragment of band 3 inhibited the incorporation of free 125I-labeled band 3 to the shells and also inhibited the Mg-ATP-dependent shape change of ghosts in the absence of Triton X-100. Both of these inhibitory effects remained, even after 10 min of heat treatment at 100 degrees C, but drastically decreased by treatment with trypsin. Our results strongly suggest that a dynamic exchange of the free band 3 for ankyrin-linked band 3 may occur in intact erythrocytes, and it may even contribute to the shape change of erythrocytes.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism* / Q000494:pharmacology; D017487:Ankyrins; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007457:Iodine Radioisotopes; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism; D017830:Octoxynol; D010446:Peptide Fragments / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology*; D014357:Trypsin / Q000494:pharmacology
D001457:Anion Exchange Protein 1, Erythrocyte; D017487:Ankyrins; D007457:Iodine Radioisotopes; D008565:Membrane Proteins; D010446:Peptide Fragments; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; D017830:Octoxynol; D014357:Trypsin