Membrane compartmentalization in Southeast Asian ovalocytosis red blood cells

Abstract

Summary Red blood cells (RBCs) from individuals with Southeast Asian ovalocytosis (SAO) contain a mutant band 3 protein that causes the formation of unique linear oligomers in the RBC membrane. We used single-particle tracking to measure the lateral diffusion of individual glycophorin C (GPC), band 3, and CD58 proteins in membranes of intact SAO RBCs and normal RBCs (nRBCs). GPC, an integral protein that binds with high affinity to the RBC membrane skeleton, showed oscillatory motion within confinement areas that were smaller in SAO RBCs than in nRBCs. The additional confinement in SAO RBCs could be due to membrane stiffening associated with the SAO phenotype. Band 3 in both SAO RBCs and nRBCs also showed confined motion over short times (ms) and distances (nm), and the area of confinement was smaller in SAO RBCs than in nRBCs. These data presumably reflect the constraints imposed by band 3 oligomerization. Similarly, the glycosylphosphatidylinositol-linked protein CD58 showed loosely confined diffusion in nRBCs and a substantially higher degree of confinement in SAO RBCs. Restricted protein mobility could contribute to the altered adherence of parasite-infected RBCs to vascular endothelium that is thought to protect individuals with SAO from severe manifestations of malaria.

Blood Groups in Infection and Host Susceptibility

“…In areas where malaria is endemic, antibodies against AE1 neoantigens are common and are believed to constitute part of the immune response (333). Relative to normal red cells, SAO cells show a high proportion of AE1 tetramers and higher-order oligomers that could alter red cell rigidity and antigenicity (528). Using singleparticle tracking, Mirchev et al documented significant decreases in membrane diffusion and mobility for AE1 and other red cell proteins (528).…”

Anatomy of the red cell membrane skeleton: unanswered questions

“…96 These percentages are remarkably similar to those of freely diffusing band 3 dimers (25%-29%) measured in normal red cells using different methods. 96,99,100 It is important to remember that some of the minor proteins found in band 3 complexes can exist only in a subset of the complexes (probably multiple different subsets) and that the lipid bilayer is heterogeneous, with areas like the lipid rafts where certain proteins concentrate. Therefore, the band 3 complexes must be more heterogeneous than these 3 states of band 3 imply.…”

Analysis of the Mobilities of Band 3 Populations Associated with Ankyrin Protein and Junctional Complexes in Intact Murine Erythrocytes

“…Moreover, fluorescence recovery after photobleaching (30,33,34) and single-particle tracking experiments (35)(36)(37) from multiple laboratories generally detect only two fractions of the anion transporter in situ. A recent paper from the Golan laboratory (38), however, observes three populations of band 3. The question thus arises whether two or three populations of band 3 actually exist in healthy erythrocytes and if three exist, whether they correlate directly with the three fractions defined in the recent biochemical studies (30 -32).…”