Calcium effects on human erythrocyte membrane proteins.

The effects of Ca2+ on human erythrocyte membrane proteins were examined by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Ca2+ had several effects on normal human erythrocyte membrane proteins. It affected the binding of cytoplasmic proteins to the membrane, produced a non-reversible aggregation of several membrane proteins and activated apparent proteolysis of membrane proteins. The Ca2+ effect could be obtained with isolated, washed membranes when the erythrocyte cytoplasm was added. These studies indicate that the Ca2+-induced membrane proteolysis and aggregation effects are not due simply to its presence at the time of hemolysis as previously suggested (Carraway, K.L., Triplett, R.B. and Anderson, D.R. (1975) Biochim. Biophys. Acta 379, 571-581), but are the result of more complex interactions between the erythrocyte membrane and cytoplasmic factors.