The erythrocyte skeletons of β-adducin deficient mice have altered levels of tropomyosin, tropomodulin and EcapZ

The erythrocyte membrane cytoskeleton is organized as a polygonal spectrin network linked to short actin filaments that are capped by adducin at the barbed ends. We have constructed a mouse strain deficient in β-adducin having abnormal erythrocytes. We show here that the levels of several skeletal proteins from β-adducin mutant erythrocytes are altered. In fact, CapZ, the main muscle actin-capping protein of the barbed ends that in the erythrocytes is cytoplasmic, is 9-fold upregulated in mutant skeletons of erythrocytes suggesting a compensatory mechanism. We also detected upregulation of tropomodulin and downregulation of α-tropomyosin and actin. In addition, purified adducin can be re-incorporated into adducin-deficient ghosts.