Intact band 3–null erythrocytes have reduced adducin content. Intact erythrocytes from wild-type (+/+) and band 3–null (−/−) mice were washed, plunged into 5× SDS-PAGE sample buffer, separated by SDS-PAGE, blotted onto nitrocellulose, and visualized with antibodies to adducin (left) and actin (right). Quantitative densitometry of 2 independent samples demonstrates a 35% decrease in adducin content of −/− erythrocytes.