Contribution of the N-linked carbohydrate of erythrocyte antigen CD59 to its complement-inhibitory activity.

Ninomiya, Hirokazu; Stewart, Betty H.; Rollins, Scott A.; Zhao, Jinmin; Bothwell, Alfred L.M.; Sims, P.

doi:10.1016/s0021-9258(18)42459-3

Cited by 62 publications

(10 citation statements)

References 26 publications

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“…A partial reduction in the affinity of the N18Q mutant for the MAC could be masked by overexpression of the protein and therefore might have gone undetected in the present study. An indirect role for the N-linked glycan in facilitating the inhibition of complement by CD59 may account for the conservation of the glycosylation site but fails to explain the observation that the enzymatically deglycosylated protein loses most of its activity (25).…”

Section: Discussionmentioning

confidence: 99%

“…Unlike the mouse Ly-6 proteins, however, CD59 is N -glycosylated at N18 (22) and this site is conserved in all known mammalian CD59 sequences except rat CD59 in which the site is shifted by two residues to N16 (23). The contribution of the N -glycan to the function of the protein is controversial, however, as its removal or modification has been variously reported to reduce costimulation of proliferation (24), and to eliminate (25), enhance (26), or have no effect on (27,28) the protective activity of CD59.…”

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confidence: 99%

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Mutational Analysis of the Active Site and Antibody Epitopes of the Complement-inhibitory Glycoprotein, CD59

Bodian

Davis

Morgan

et al. 1997

The Journal of Experimental Medicine

124

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The Ly-6 superfamily of cell surface molecules includes CD59, a potent regulator of the complement system that protects host cells from the cytolytic action of the membrane attack complex (MAC). Although its mechanism of action is not well understood, CD59 is thought to prevent assembly of the MAC by binding to the C8 and/or C9 proteins of the nascent complex. Here a systematic, structure-based mutational approach has been used to determine the region(s) of CD59 required for its protective activity. Analysis of 16 CD59 mutants with single, highly nonconservative substitutions suggests that CD59 has a single active site that includes Trp-40, Arg-53, and Glu-56 of the glycosylated, membrane-distal face of the disk-like extracellular domain and, possibly, Asp-24 positioned at the edge of the domain. The putative active site includes residues conserved across species, consistent with the lack of strict homologous restriction previously observed in studies of CD59 function. Competition and mutational analyses of the epitopes of eight CD59-blocking and non-blocking monoclonal antibodies confirmed the location of the active site. Additional experiments showed that the expression and function of CD59 are both glycosylation independent.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Mutational Analysis of the Active Site and Antibody Epitopes of the Complement-inhibitory Glycoprotein, CD59

Bodian

Davis

Morgan

et al. 1997

The Journal of Experimental Medicine

124

View full text Add to dashboard Cite

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“…25 This further supports the assumption that the carbohydrates do not contribute to its function to bind C8/C9, but are necessary for the three-dimensional orientation of the molecule. Ninomiya et al 26 suggested that the N-linked glycan may dampen the flexibility of CD59 and may keep the active site in the proper orientation for interaction with the membrane attack complex (MAC). This role for the N-glycan of CD59 was suggested by the finding that deglycosylated CD59 lost its ability to prevent lysis, but showed no differences in binding to plastic-adsorbed C8 and C9.…”

Section: Molecular Basis and Biochemistrymentioning

confidence: 99%

CD59: A long-known complement inhibitor has advanced to a blood group system

Weinstock

Zabern

2015

Immunohematology

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The blood group system number 35 is based on CD59, a 20-kDa membrane glycoprotein present on a large number of different cells, including erythrocytes. The major function of CD59 is to protect cells from complement attack. CD59 binds to complement components C8 and C9 and prevents the polymerization of C9, which is required for the formation of the membrane attack complex (MAC). Other functions of CD59 in cellular immunity are less well defined. CD59 is inserted into the membrane by a glycosylphosphatidylinositol (GPI) anchor. A defect of this anchor causes lack of this protein from the cell membrane, which leads to an enhanced sensitivity towards complement attack. Patients with paroxysmal nocturnal hemoglobinuria (PNH) harbor a varying percentage of red blood cell clones with a defect in GPI-anchored proteins, including CD59. The most characteristic symptoms of this disease are episodes of hemolysis and thromboses. Although CD59 has been classified as a membrane protein for more than 25 years, an alloantibody directed against CD59 was found only recently. So far, the first and sole alloantibody described was detected in a CD59-deficient child. In 2014, CD59 received the status of a blood group system by the International Society for Blood Transfusion Red Cell Immunogenetics and Blood Group Terminology Working Party. Among a variety of almost 20 synonyms, the designation CD59 was chosen for the blood group system and CD59.1 for the wild-type protein. The only three alleles published to date are null alleles. All CD59-deficient individuals recognized so far were severely ill, two of whom have died. Most of the reported cases present with a typical clinical picture within the first year of life that includes neuropathy, strokes, and mild Coombs-negative hemolysis. In one published case, the application of the complement inhibitor eculizumab caused a pronounced improvement of the clinical situation.

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“…In addition, the present findings provide a strategy for the design of soluble and membrane inhibitors of the terminal complement proteins. Akami et al (42), and Dong and Tomlinson (unpublished observations) have shown that recombinant CD59 is more effective as an inhibitor of C5b-9 when it lacks the asparagine-linked oligosaccharide which contains sialic acid (42,43). W e would predict that any recombinant inhibitor of the membrane attack complex should lack sialic acid for maximal activity.…”

Section: Name Variations In Neu5acmentioning

confidence: 99%

Interaction between complement proteins C5b-7 and erythrocyte membrane sialic acid.

Marshall

Hasegawa

Davidson

et al. 1996

The Journal of Experimental Medicine

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The initial, phase of membrane attack by complement is the interaction between C5b6, C7, and the cell membrane that leads to the insertion of C5b-7. Here we investigate the role of sialic acid residues in the assembly of C5b-7 intermediates on erythrocyte cell membranes. We find that C5b6 binds to glycophorin, whereas C5 or C6 does not bind, and desialylation of the glycophorin abolishes C5b6 binding. Complement lysis is inhibited by either masking glycophorin sialic acid with F~b fragments of an mAb, or by removal of the sialylated region of glycophorin by mild trypsinization. Gangliosides inhibit C5b-7 deposition when added to the aqueous phase. Asialogangliosides and synthetic gangliosides lacking the carboxylic acid residue have no inhibitory activity. We conclude that C5b6 binds to sialylated molecules on the erythrocyte surface. We propose a new model of membrane attack in which C5b6 initially binds to membranes via ionic forces. C7 then binds to C5b6, disrupting the ionic interaction and leading to the exposure of hydrophobic domains. Sialic acid is known to inhibit complement activation. Thus, these findings reveal a paradoxical role for sialic acid in complement attack; the presence of sialic acid inhibits the generation of C5b6, but once the membrane attack pathway is initiated, sialic acid enhances complement lysis.

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Contribution of the N-linked carbohydrate of erythrocyte antigen CD59 to its complement-inhibitory activity.

Cited by 62 publications

References 26 publications

Mutational Analysis of the Active Site and Antibody Epitopes of the Complement-inhibitory Glycoprotein, CD59

Mutational Analysis of the Active Site and Antibody Epitopes of the Complement-inhibitory Glycoprotein, CD59

CD59: A long-known complement inhibitor has advanced to a blood group system

Interaction between complement proteins C5b-7 and erythrocyte membrane sialic acid.

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