Hereditary spherocytosis and hereditary elliptocytosis: aberrant protein sorting during erythroblast enucleation

Blood. 2010 Jul 15;116(2):267-9. doi: 10.1182/blood-2010-02-264127. Epub 2010 Mar 25.

Abstract

During erythroblast enucleation, membrane proteins distribute between extruded nuclei and reticulocytes. In hereditary spherocytosis (HS) and hereditary elliptocytosis (HE), deficiencies of membrane proteins, in addition to those encoded by the mutant gene, occur. Elliptocytes, resulting from protein 4.1R gene mutations, lack not only 4.1R but also glycophorin C, which links the cytoskeleton and bilayer. In HS resulting from ankyrin-1 mutations, band 3, Rh-associated antigen, and glycophorin A are deficient. The current study was undertaken to explore whether aberrant protein sorting, during enucleation, creates these membrane-spanning protein deficiencies. We found that although glycophorin C sorts to reticulocytes normally, it distributes to nuclei in 4.1R-deficient HE cells. Further, glycophorin A and Rh-associated antigen, which normally partition predominantly to reticulocytes, distribute to both nuclei and reticulocytes in an ankyrin-1-deficient murine model of HS. We conclude that aberrant protein sorting is one mechanistic basis for protein deficiencies in HE and HS.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anion Exchange Protein 1, Erythrocyte / metabolism
  • Blood Proteins / deficiency
  • Blood Proteins / genetics
  • Blood Proteins / metabolism
  • Cell Nucleus / metabolism
  • Elliptocytosis, Hereditary / genetics
  • Elliptocytosis, Hereditary / metabolism*
  • Elliptocytosis, Hereditary / pathology
  • Erythroblasts / metabolism*
  • Erythrocyte Membrane / metabolism
  • Erythrocyte Membrane / pathology
  • Erythropoiesis / physiology*
  • Fluorescent Antibody Technique
  • Glycophorins / metabolism
  • Membrane Glycoproteins / metabolism
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Mutant Strains
  • Microfilament Proteins
  • Mutation
  • Protein Transport
  • Spherocytosis, Hereditary / genetics
  • Spherocytosis, Hereditary / metabolism*
  • Spherocytosis, Hereditary / pathology

Substances

  • Anion Exchange Protein 1, Erythrocyte
  • Blood Proteins
  • Epb41 protein, mouse
  • Glycophorins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Microfilament Proteins
  • Rhag protein, mouse