Erythrocyte band

Active transport of a molecule across a membrane against its concentration gradient requires an input of metabolic energy. In the case of ATP-driven active transport, the energy required for the transport of the molecule (Na+, K+, Ca2+ or H+) across the membrane is derived from the coupled hydrolysis of ATP (e.g Na+/K+-ATPase). In ion-driven active transport, the movement of the molecule to be transported across the membrane is coupled to the movement of an ion (either Na+ or H+) down its concentration gradient. If both the molecule to be transported and the ion move in the same direction across the membrane, the process is called symport (e.g. Na+/glucose transporter) if the molecule and the ion move in opposite directions it is called antiport (e.g. erythrocyte band 3 anion transporter). 

Fig. 4. Ion-driven cotransport mechanisms, (a) Symport process involving a symporter (e.g. Na+/glucose transporter) (b) antiport process involving an antiporter (e.g. erythrocyte band 3 anion transporter).

Erythrocyte band 7 integral membrane protein (stomatin) P27105 2.6 0.3... 

Nuclear pore proteins [33,37,44,85-87] Human erythrocyte band 4.1 [66]... 

Many of the cytosolic O-GlcNAc modified proteins that have been identified are components of the cellular cytoskeleton. The first to be characterized was human erythrocyte Band 4.1 [66]. This protein is involved in maintaining the unique shape of erythrocytes by anchoring actin and spectrin to the cytoplasmic tail of glycophorin. While preliminary studies suggested that only the glycosylated forms of Band 4.1 binds to the cytoskeleton, additional controlled studies are needed to confirm this finding. 

Lucas, J. Z., and Sherman, I. W. (1998). Plasmodium falciparum Thrombospondin mediates parasitized erythrocyte band 3-related adhesin binding. Exp. Parasitol. 89,78-85. 

Roggwiller, E., Betoulle, M. E., Blisnick, T., and Braun Breton, C. (1996). A role for erythrocyte band 3 degradation by the parasite gp76 serine protease in the formation of the para-sitophorous vacuole during invasion of erythrocytes by Plasmodium falciparum. Mol. Biochem. Parasitol. 82,13-24. 

Winograd, E., and Sherman, I. W. (2004). Malaria infection induces a conformational change in erythrocyte band 3 protein. Mol. Biochem. Parasitol. 138, 83-87. 

M. L. Jennings, M. P. Anderson, and R. Monaghan, Monoclonal antibodies against human erythrocyte band 3 protein, J. Biol Chem. 261, 9002-9010 (1986). 

The extent to which the level of galactose-l-phosphate uridyl transferase activity in erythrocytes reflects the level in the liver is unknown except for a bandful of cases. This problem is worth further investigation with particular reference to these 2 groups of heterozygotes, those showing unusual galactose intolerance and those with very low enzymatic activity. 

Maneri, L.R. and P.S. Low. 1988. Structural stability of the erythrocyte anion transporter, band 3, in different lipid environments. A differential scanning calorimetric study. J Biol Chem 263 16170-16178. 

Figure 3. Critical concentration behavior of actin self-assembly. For the top diagram depicting the macroscopic critical concentration curve, one determines the total amount of polymerized actin by methods that measure the sum of addition and release processes occurring at both ends. Examples of such methods are sedimentation, light scattering, fluorescence assays with pyrene-labeled actin, and viscosity measurements. Forthe bottom curves, the polymerization behavior is typically determined by fluorescence assays conducted under conditions where one of the ends is blocked by the presence of molecules such as gelsolin (a barbed-end capping protein) or spectrin-band 4.1 -actin (a complex prepared from erythrocyte membranes, such that only barbed-end growth occurs). Note further that the barbed end (or (+)-end) has a lower critical concentration than the pointed end (or (-)-end). This differential stabilization requires the occurrence of ATP hydrolysis to supply the free energy that drives subunit addition to the (+)-end at the expense of the subunit loss from the (-)-end.

The observation by Maddy and Malcolm (53) that the amide I band of bovine erythrocyte ghosts in D20 is not shifted is remarkable because it implies that all of the membrane protein is either deeply buried in an environment of hydrophobic lipids or exists in a tightly folded a-helical conformation. We have examined extensively the infrared spectra of bovine erythrocyte ghosts, both as dry films and as intact ghosts in D20 and H20 (73). The results for dry films essentially agree with those of other workers and show no evidence of f3 structure. Little change occurs in water. In D20, however, we consistently obtained a shift in the amide I band and a considerable decrease in absorption of the amide II band. 

Figure 7. Infrared spectra of erythrocyte membranes (a) dry, (b) in D2O-0.1M NaCl for 1.5 hours, and (c) heated to 100°C. in D2O-0.1 M NaCl for 10 minutes. Spectra were taken in CaF2 cells. The residual amide 11 band at 1540 cm. 1 indicates incomplete exchange in D20, and disappears on heating. The shoulder at 1618 cm. 1 on the amide I band of heated membranes suggests aggregated fi structure...

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