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

Blood ◽  
2010 ◽  
Vol 116 (2) ◽  
pp. 267-269 ◽  
Author(s):  
Marcela Salomao ◽  
Ke Chen ◽  
Jonathan Villalobos ◽  
Narla Mohandas ◽  
Xiuli An ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Hereditary Spherocytosis ◽  
Protein Sorting ◽  
Gene Mutations ◽  
Mutant Gene ◽  
Glycophorin A ◽  
Hereditary Elliptocytosis ◽  
Aberrant Protein ◽  
Mechanistic Basis ◽  
Glycophorin C

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.

Aberrant Protein Sorting to the Nucleus during Erythroblast Enucleation: Mechanistic Basis for Membrane Protein Loss in Hereditary Elliptocytosis and Spherocytosis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1559-1559
Author(s):  
Marcela A. Salomao ◽  
Sarah Short ◽  
Gloria Lee ◽  
Xiuli An ◽  
Mohandas Narla ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Plasma Membranes ◽  
Molecular Mechanisms ◽  
Protein Sorting ◽  
Transmembrane Proteins ◽  
Hereditary Elliptocytosis ◽  
Skeletal Protein ◽  
Aberrant Protein ◽  
Protein 4.1R

Abstract During erythroblast enucleation, nuclei surrounded by plasma membrane separate from erythroblast cytoplasm. A key aspect of this process is sorting of membrane components to plasma membranes surrounding expelled nuclei and young reticulocytes. This protein partitioning performs a crucial role in regulating the protein content of reticulocyte plasma membranes. Although it is known that cytoskeletal actin, spectrin and protein 4.1R distribute to reticulocytes, little is known about the sorting patterns of erythroblast transmembrane proteins. In hereditary spherocytosis (HS) and hereditary elliptocytosis (HE), erythrocytes contain well-described deficiencies of various transmembrane proteins, in addition to those encoded by the mutant genes. For example, elliptocytic human and murine erythrocytes resulting from mutations in the 4.1R gene lack not only protein 4.1R but also transmembrane protein glycophorin C (GPC), known to be a 4.1R binding partner with a key role in linking cytoskeleton to bilayer. Similarly, in HS resulting from mutations in the ankyrin gene, deficiencies of band 3, Rh and GPA have been documented. Various molecular mechanisms could explain deficiencies of membrane proteins in HS and HE erythrocytes including: perturbed trafficking to the erythroblast membrane; aberrant protein sorting during erythroblast enucleation; and selective loss during reticulocyte membrane remodeling. We explored whether aberrant protein sorting during enucleation might be responsible for GPC deficiency in HE. First we performed immunochemical analysis of the sorting pattern of GPC using highly purified extruded nuclei and immature reticulocytes derived from terminally differentiated murine erythroblast cultures. Proteins from equivalent numbers of expelled nuclei and reticulocytes were analyzed by Western blotting. Using antibodies specific for GPC we determined that 90% of GPC sorted to reticulocyte plasma membranes. To validate these results we used live cell, three-color immunofluorescent microscopy and analyzed enucleating erythroblasts, reticulocytes and extruded nuclei from freshly harvested murine wild type bone marrow. Independently confirming the Western blot data, we found that GPC sorted almost exclusively to reticulocytes with little or no GPC in association with nuclear plasma membrane. Strikingly, in 4.1R null erythroblasts GPC was distributed exclusively to expelled nuclei. These findings unequivocally establish that skeletal protein 4.1R is critical for normal sorting of GPC to young reticulocytes and provide clear evidence that specific skeletal protein associations can regulate protein sorting during enucleation. Moreover, our data provide a molecular explanation for the underlying basis of GPC deficiency observed in 4.1R-deficient individuals with HE. We speculate that aberrant protein sorting may be a prevalent mechanism for the deficiencies of various membrane proteins in HS and HE and that their differential loss could contribute to the variable phenotypic expression of these hemolytic disorders.

scholarly journals Characterization of 13 novel band 3 gene defects in hereditary spherocytosis with band 3 deficiency

Blood ◽  
1996 ◽  
Vol 88 (11) ◽  
pp. 4366-4374 ◽  
Author(s):  
P Jarolim ◽  
JL Murray ◽  
HL Rubin ◽  
WM Taylor ◽  
JT Prchal ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Autosomal Dominant ◽  
Hereditary Spherocytosis ◽  
Gene Mutations ◽  
Band 3 ◽  
Red Cell Membrane ◽  
Cell Membrane Proteins ◽  
Gene Defects ◽  
Relative Deficiency ◽  
Peripheral Blood Smears

Abstract Hereditary spherocytosis (HS) is a common hemolytic anemia of variable clinical expression. Pathogenesis of HS has been associated with defects of several red cell membrane proteins including erythroid band 3. We have studied erythrocyte membrane proteins in 166 families with autosomal dominant HS. We have detected relative deficiency of band 3 in 38 kindred (23%). Band 3 deficiency was invariably associated with mild autosomal dominant spherocytosis and with the presence of pincered red cells in the peripheral blood smears of unsplenectomized patients. We hypothesized that this phenotype is caused by band 3 gene defects. Therefore, we screened band 3 DNA from these 38 kindred for single strand conformational polymorphisms (SSCP). In addition to five mutations detected previously by SSCP screening of cDNA, we detected 13 new band 3 gene mutations in 14 kindred coinherited with HS. These novel mutations consisted of two distinct subsets. The first subset included seven nonsense and frameshift mutations that were all associated with the absence of the mutant mRNA allele from reticulocyte RNA, implicating decreased production and/or stability of mutant mRNA as the cause of decreased band 3 synthesis. The second group included five substitutions of highly conserved amino acids and one in-frame deletion. These six mutations were associated with the presence of comparable levels of normal and mutant band 3 mRNA. We suggest that these mutations interfere with band 3 biosynthesis leading thus to the decreased accumulation of the mutant band 3 allele in the plasma membrane.

scholarly journals Characterization of 13 novel band 3 gene defects in hereditary spherocytosis with band 3 deficiency

Blood ◽  
1996 ◽  
Vol 88 (11) ◽  
pp. 4366-4374 ◽  
Author(s):  
P Jarolim ◽  
JL Murray ◽  
HL Rubin ◽  
WM Taylor ◽  
JT Prchal ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Autosomal Dominant ◽  
Hereditary Spherocytosis ◽  
Gene Mutations ◽  
Band 3 ◽  
Red Cell Membrane ◽  
Cell Membrane Proteins ◽  
Gene Defects ◽  
Relative Deficiency ◽  
Peripheral Blood Smears

Hereditary spherocytosis (HS) is a common hemolytic anemia of variable clinical expression. Pathogenesis of HS has been associated with defects of several red cell membrane proteins including erythroid band 3. We have studied erythrocyte membrane proteins in 166 families with autosomal dominant HS. We have detected relative deficiency of band 3 in 38 kindred (23%). Band 3 deficiency was invariably associated with mild autosomal dominant spherocytosis and with the presence of pincered red cells in the peripheral blood smears of unsplenectomized patients. We hypothesized that this phenotype is caused by band 3 gene defects. Therefore, we screened band 3 DNA from these 38 kindred for single strand conformational polymorphisms (SSCP). In addition to five mutations detected previously by SSCP screening of cDNA, we detected 13 new band 3 gene mutations in 14 kindred coinherited with HS. These novel mutations consisted of two distinct subsets. The first subset included seven nonsense and frameshift mutations that were all associated with the absence of the mutant mRNA allele from reticulocyte RNA, implicating decreased production and/or stability of mutant mRNA as the cause of decreased band 3 synthesis. The second group included five substitutions of highly conserved amino acids and one in-frame deletion. These six mutations were associated with the presence of comparable levels of normal and mutant band 3 mRNA. We suggest that these mutations interfere with band 3 biosynthesis leading thus to the decreased accumulation of the mutant band 3 allele in the plasma membrane.

A spin-label study of membrane proteins and internal microviscosity of erythrocytes in hereditary spherocytosis

Life Sciences ◽  
1987 ◽  
Vol 41 (20) ◽  
pp. 2285-2288 ◽  
Author(s):  
G. Bartosz ◽  
M. Gaczyńska ◽  
E. Grzelińska ◽  
L. Judkiewicz
Keyword(s):  
Membrane Proteins ◽  
Spin Label ◽  
Hereditary Spherocytosis ◽  
Label Study

scholarly journals Disorders of the erythrocyte membrane

2015 ◽  
Vol 9 (4) ◽  
pp. 323
Author(s):  
Sophia Delicou ◽  
Aikaterini Xydaki ◽  
Chryssanthi Kontaxi ◽  
Konstantinos Maragkos
Keyword(s):  
Surface Area ◽  
Erythrocyte Membrane ◽  
Structural Integrity ◽  
Mechanical Stability ◽  
Hereditary Spherocytosis ◽  
Membrane Surface ◽  
Membrane Skeleton ◽  
Inherited Disorders ◽  
Hereditary Elliptocytosis ◽  
Area Loss

Hemolytic anemia due to abnormalities of the erythrocyte membrane comprises an important group of inherited disorders. These include hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis, and the hereditary stomatocytosis syndromes. The erythrocyte membrane skeleton composed of spectrin, actin, and several other proteins is essential for the maintenance of the erythrocyte shape, reversible deformability, and membrane structural integrity in addition to controlling the lateral mobility of integral membrane proteins. These disorders are characterized by clinical and laboratory heterogeneity and, as evidenced by recent molecular studies, by genetic heterogeneity. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Treatment with splenectomy is curative in most patients.

Endogenous phosphorylation of membrane proteins in normal and in hereditary spherocytosis erythrocytes

1977 ◽  
Vol 77 (3) ◽  
pp. 359-363 ◽  
Author(s):  
V. Moret ◽  
Elena Michielin ◽  
G.C. Falezza ◽  
G. De Sandre
Keyword(s):  
Membrane Proteins ◽  
Hereditary Spherocytosis

Recruitment of the endosomal WASH complex is mediated by the extended ‘tail’ of Fam21 binding to the retromer protein Vps35

2012 ◽  
Vol 442 (1) ◽  
pp. 209-220 ◽  
Author(s):  
Michael E. Harbour ◽  
Sophia Y. Breusegem ◽  
Matthew N. J. Seaman
Keyword(s):  
Membrane Proteins ◽  
Protein Sorting ◽  
Complex Interaction ◽  
Membrane Association ◽  
Tail Domain ◽  
Fk506 Binding Protein ◽  
Retromer Complex ◽  
Multimeric Protein ◽  
Vacuolar Protein ◽  
Necessary And Sufficient

The retromer complex is a conserved endosomal protein sorting complex that sorts membrane proteins into nascent endosomal tubules. The recognition of membrane proteins is mediated by the cargo-selective retromer complex, a stable trimer of the Vps35 (vacuolar protein sorting 35), Vps29 and Vps26 proteins. We have recently reported that the cargo-selective retromer complex associates with the WASH (Wiskott–Aldrich syndrome homologue) complex, a multimeric protein complex that regulates tubule dynamics at endosomes. In the present study, we show that the retromer–WASH complex interaction occurs through the long unstructured ‘tail’ domain of the WASH complex–Fam21 protein binding to Vps35, an interaction that is necessary and sufficient to target the WASH complex to endosomes. The Fam21-tail also binds to FKBP15 (FK506-binding protein 15), a protein associated with ulcerative colitis, to mediate the membrane association of FKBP15. Elevated Fam21-tail expression inhibits the association of the WASH complex with retromer, resulting in increased cytoplasmic WASH complex. Additionally, overexpression of the Fam21-tail results in cell-spreading defects, implicating the activity of the WASH complex in regulating the mobilization of membrane into the endosome-to-cell surface pathway.

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