Adducin forms a bridge between the erythrocyte membrane and its cytoskeleton and regulates membrane cohesion.
The erythrocyte membrane skeleton is the best understood cytoskeleton. Because its protein components have homologs in virtually all other cells, the membrane serves as a fundamental model of biologic membranes. Modern textbooks portray the membrane as a 2-dimensional spectrin-based membrane skeleton attached to a lipid bilayer through 2 linkages: band 3-ankyrin-beta-spectrin and glycophorin C-protein 4.1-beta-spectrin.(1-7) Although evidence supports an essential role for the first bridge in regulating membrane cohesion, rupture of the glycophorin C-protein 4.1 interaction has little effect on membrane stability.(8) We demonstrate the existence of a novel band 3-adducin-spectrin bridge that connects the spectrin/actin/protein 4.1 junctional complex to the bilayer. As rupture of this bridge leads to spontaneous membrane fragmentation, we conclude that the band 3-adducin-spectrin bridge is important to membrane stability. The required relocation of part of the band 3 population to the spectrin/actin junctional complex and its formation of a new bridge with adducin necessitates a significant revision of accepted models of the erythrocyte membrane.
Anong
William A
WA
Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA.
Franco
Taina
T
Chu
Haiyan
H
Weis
Tahlia L
TL
Devlin
Emily E
EE
Bodine
David M
DM
An
Xiuli
X
Mohandas
Narla
N
Low
Philip S
PS
D000199:Actins / Q000378:metabolism; D019921:Biotinylation; D002148:Calmodulin-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism; D008954:Models, Biological; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D020349:Surface Plasmon Resonance; D000099291:Adducins
D000199:Actins; D002148:Calmodulin-Binding Proteins; D005982:Glutathione Transferase; D008051:Lipid Bilayers; D011994:Recombinant Proteins; D000099291:Adducins