Chronology of the formation of vesicles and membrane protein aggregates during erythrocyte aging.

The aim of the present work was to study the changes undergone by proteins in ghost cells, vesicles and membrane protein aggregates during erythrocyte aging. As a model of cell, whole blood collected into CPD was stored for eight weeks at +4 degrees C. SDS-PAGE and immunoblotting with antibodies against spectrin and band 3 showed that vesicles were mainly composed of band 3 and were devoid of spectrin, whereas membrane protein aggregates contained several membrane proteins but in a more advanced state of degradation. A study of spectrin and band 3 in the ghosts, vesicles and protein aggregates revealed increasing fragmentation of both proteins with storage time. Since this degradation was most important in membrane protein aggregates, it was possible to establish the chronological order of appearance of vesicles and aggregates. In view of our observations, we propose that membrane protein aggregates may be regarded as replacement structures resulting from membrane rearrangements occurring after the emission of vesicles.