Publications [#112925] of G Vann V. Bennett

Papers Published

1. P Agre, EP Orringer, DH Chui, V Bennett, A molecular defect in two families with hemolytic poikilocytic anemia: reduction of high affinity membrane binding sites for ankyrin., The Journal of clinical investigation, UNITED STATES, vol. 68 no. 6 (December, 1981), pp. 1566-76, ISSN 0021-9738
   (last updated on 2003/02/18)

   Abstract:
   Patients from two families with chronic hemolytic anemia have been studied. The erythrocytes are very fragile and appear microcytic with a great variety of shapes. Clinical evaluation failed to identify traditionally recognized causes of hemolysis. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed no significant abnormality of the major polypeptide bands. Erythrocytes spectrin-ankyrin and ankyrin-membrane interactions were analyzed with 125I-labeled spectrin, 125I-labeled ankyrin, and inside-out vesicles. Patients' vesicles bound 125I-spectrin normally. Likewise, patients' spectrin and ankyrin competed normally for the binding sites on control membranes. None of the individual components appeared to have abnormal thermal sensitivity. Ankyrin-stripped, inside-out vesicles prepared from the patients bound less 125I-ankyrin than did vesicles prepared from normals (P less than 0.05 for all corresponding points in the high-affinity region). Scatchard analysis showed the most significant abnormality to be a 50% reduction in the high affinity ankyrin binding sites. Similar experiments were performed with blood from patients with spherocytosis and splenectomized controls, but no abnormalities were detected. The water soluble 43,000-dalton fragments of band 3 (the high-affinity ankyrin binding sites) were prepared from one of the patients and competed normally for 125I-ankyrin binding in solution. This suggests that the primary structural defect is a reduction in the number of high affinity membrane binding sites for ankyrin, and is consistent with an abnormal organization of band 3 in the membrane.

   Keywords:
   Adult • Aged • Anemia, Hemolytic • Ankyrins • Binding Sites • Binding, Competitive • Cell Membrane • Electrophoresis, Polyacrylamide Gel • Erythrocytes, Abnormal • Female • Humans • Male • Membrane Proteins • Microscopy, Electron, Scanning • Peptides • Protein Binding • Spectrin • Splenectomy • analysis • blood* • metabolism • metabolism* • ultrastructure