Clarification of role of ATP in red-cell morphology and function

Abstract

RECENTLY there has been a tendency to ascribe many energy-dependent functions of other types of cells to red cells. The widespread belief that red cell form and deformability depend on cellular ATP levels and that membrane internalisation is an energy-dependent phenomenon are cases in point^1–4. ATP has indeed been shown to control phagocytosis, pinocytosis and locomotion in white cells; the confusion over whether it is pinocytosis (which requires energy) or endovesicle formation (which does not) that occurs in erythrocytes may be due to the observation⁵ of the former phenomenon in erythrocyte precursors (erythroblasts and reticulocytes). To establish that pinocytosis occurs also in the ultimate cell of the series—the erythrocyte—it is necessary to demonstrate that internalisation of the cell membrane is dependent on energy; and thus on temperature, pH, time, and ATP. This is not the case and results of the investigation described here show that ATP does not directly control either the form and deformability or membrane internalisation of red cells and that phenomena secondary to ATP depletion are responsible for the changes induced.