Regulation of band 3 rotational mobility by ankyrin in intact human red cells.
Biochemistry
; 37(51): 17828-35, 1998 Dec 22.
Article
em En
| MEDLINE
| ID: mdl-9922149
ABSTRACT
Ankyrin mutations and combined spectrin and ankyrin deficiency are prominent features of red blood cells (RBCs) in patients with hereditary spherocytosis (HS). Band 3 is the most abundant integral protein in the human RBC membrane. Previous studies have shown that the lateral mobility, but not the rotational mobility, of band 3 is increased in RBCs from patients with severe autosomal recessive HS and selective spectrin deficiency. These observations are consistent with the steric hindrance model of lateral mobility restriction. Here we use the fluorescence photobleaching recovery and polarized fluorescence depletion techniques to measure the lateral and rotational mobility of band 3 in intact RBCs from six patients with HS, ankyrin mutations, and combined spectrin and ankyrin deficiency. As predicted by the steric hindrance model, the lateral diffusion rate of band 3 is greater in spectrin- and ankyrin-deficient RBCs than in control cells, and the magnitude of the increase correlates with the degree of spectrin deficiency. Unlike RBCs from patients with HS and selective spectrin deficiency, however, HS RBCs with ankyrin mutations exhibit a marked increase in band 3 rotational diffusion. The magnitude of the increase correlates inversely with the ankyrin/band 3 ratio and with the fraction of band 3 retained in the membrane skeleton following detergent extraction. These data suggest that ankyrin deficiency relaxes rotational constraints on the major (slowly rotating) population of band 3 molecules. Increases in band 3 rotation could be due to release of band 3 from low-affinity binding sites on ankyrin.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteína 1 de Troca de Ânion do Eritrócito
/
Anquirinas
Tipo de estudo:
Prognostic_studies
Limite:
Female
/
Humans
Idioma:
En
Revista:
Biochemistry
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Estados Unidos