Increased ion permeability of planar lipid bilayer membranes after treatment with the C5b-9 cytolytic attack mechanism of complement.

Michaels, David; Abramovitz, Aaron S.; Hammer, Carl H.; Mayer, Manfred M.

doi:10.1073/pnas.73.8.2852

Cited by 91 publications

(37 citation statements)

References 23 publications

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“…Downstream of C3 activation, C3 convertase participates in the formation of C5 convertase, a membrane-bound complex that cleaves serum C5 into C5a and C5b. C5b induces sequential recruitment of complement proteins C6, C7, C8, and C9 to form C5b-9, the terminal complement complex, which creates a pore in the membrane (2).…”

Section: Introductionmentioning

confidence: 99%

C3b deposition on human erythrocytes induces the formation of a membrane skeleton–linked protein complex

Karnchanaphanurach

Mirchev²,

Ghiran³

et al. 2009

J. Clin. Invest.

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Decay-accelerating factor (DAF, also known as CD55), a glycosylphosphatidylinositol-linked (GPI-linked) plasma membrane protein, protects autologous cells from complement-mediated damage by inhibiting complement component 3 (C3) activation. An important physical property of GPI-anchored complement regulatory proteins such as DAF is their ability to translate laterally in the plasma membrane. Here, we used singleparticle tracking and tether-pulling experiments to measure DAF lateral diffusion, lateral confinement, and membrane skeletal associations in human erythrocyte membranes. In native membranes, most DAF molecules exhibited Brownian lateral diffusion. Fluid-phase complement activation caused deposition of C3b, one of the products of C3 cleavage, onto erythrocyte glycophorin A (GPA). We then determined that DAF, C3b, GPA, and band 3 molecules were laterally immobilized in the membranes of complement-treated cells, and GPA was physically associated with the membrane skeleton. Mass spectrometry analysis further showed that band 3, α-spectrin, β-spectrin, and ankyrin were present in a complex with C3b and GPA in complement-treated cells. C3b deposition was also associated with a substantial increase in erythrocyte membrane stiffness and/or viscosity. We therefore suggest that complement activation stimulates the formation of a membrane skeletonlinked DAF-C3b-GPA-band 3 complex on the erythrocyte surface. This complex may promote the removal of senescent erythrocytes from the circulation. IntroductionThe complement system is a major effector component of the innate immune response (1). The complement cascade, which involves sequential activation of serum complement proteins, leads to diverse inflammatory effects and, in some cases, lysis of the target. Activation of complement can occur through the classical, alternative, and lectin pathways. All 3 pathways lead to the formation of complement component 3 (C3) convertase, a central enzymatic complement complex that cleaves serum C3 into C3a and C3b. C3b can dock covalently on a membrane surface via amide or ester linkages. Downstream of C3 activation, C3 convertase participates in the formation of C5 convertase, a membrane-bound complex that cleaves serum C5 into C5a and C5b. C5b induces sequential recruitment of complement proteins C6, C7, C8, and C9 to form C5b-9, the terminal complement complex, which creates a pore in the membrane (2).

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Section: Introductionmentioning

confidence: 99%

C3b deposition on human erythrocytes induces the formation of a membrane skeleton–linked protein complex

Karnchanaphanurach

Mirchev²,

Ghiran³

et al. 2009

J. Clin. Invest.

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“…The number ofC9 molecules per complex (n) is believed to be one to two in homologous cell/serum systems and three to four in heterologous systems (1). The MAC is a transmembrane pore which is functionally expressed as an increased membrane permeability (2,3). The cation leak through the MAC can lead to colloidosmotic swelling and lysis of the target cell or, at sublytic concentrations, to large but reversible changes in the internal composition of the cell (4).…”

Section: Introductionmentioning

confidence: 99%

Terminal complement complex C5b-9 stimulates mitogenesis in 3T3 cells.

Halperin¹,

Taratuska²,

Nicholson‐Weller³

1993

J. Clin. Invest.

115

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The membrane attack complex of complement (MAC) can induce reversible changes in cell membrane permeability resulting in significant but transient intracellular ionic changes in the absence of cell lysis. Because ion fluxes and cytosolic ionic changes are integral steps in the signaling cascade initiated when growth factors bind to their receptors, we hypothesized that the MAC-induced reversible changes in membrane permeability could stimulate cell proliferation. Using purified terminal complement components we have documented a mitogenic effect of the MAC for quiescent murine 3T3 cells. The MAC enhances the mitogenic effects of serum and PDGF, and also stimulates cell proliferation in the absence of other exogenous growth factors. MAC-induced mitogenesis represents a novel effect of the terminal complement complex that could contribute to focal tissue repair or pathological cell proliferation locally at sites of complement activation. (J. Clin. Invest. 1993.

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“…The subsequent interactions among the terminal complement proteins (C5b-C9) are accompanied by exposure of hydrophobic peptides (2)(3)(4). If this occurs in the immediate vicinity of a bilayer membrane, some of the exposed peptides become inserted in the lipid bilayer (5)(6)(7)(8) and are assembled into transmembrane channels (9)(10)(11)(12).…”

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confidence: 99%

Transmembrane channel formation by complement: functional analysis of the number of C5b6, C7, C8, and C9 molecules required for a single channel.

Ramm¹,

Whitlow²,

Mayer³

1982

Proc. Natl. Acad. Sci. U.S.A.

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Earlier studies have shown that sequential treatment of resealed erythrocyte ghosts with C5b6, C7, C8, and C9 leads to insertion ofhydrophobic peptides from these complement proteins into the membrane and assembly of transmembrane channels. The number of molecules of each of the proteins required for assembly of the membrane-associated channel structure was evaluated by measuring the quantitative relationship between the doses ofthe individual proteins and the release of two trapped markers, sucrose and inulin, from ghosts after channel formation. The incubation period was sufficient to attain equilibrium of marker distribution between the ghosts and the extracellular fluid. Two markers of different size (sucrose and inulin, 0.9 and 3 nm molecular diameter, respectively) were used in order to develop information on the molecular composition of small and large channels, respectively. We found that participation of C5b6, C7, and C8 in channel formation displayed one-hit characteristics, regardless of marker size. By contrast, the participation of C9 was one-hit with respect to the sucrose marker, whereas with respect to the inulin marker the C9 reaction was multi-hit. Our results are compatible with the view that these markers are released through a channel structure in the membrane that is a monomer of C5b-9 of the composition C5b61C71C81C9., in which n = 1 for channels permitting passage of sucrose and n = 2 for channels allowing transit of inulin.Membrane attack by complement is initiated when complement protein C5 is cleaved into C5a and C5b by the C5 convertase of either the classical or the alternative activation pathway (1). The subsequent interactions among the terminal complement proteins (C5b-C9) are accompanied by exposure of hydrophobic peptides (2-4). If this occurs in the immediate vicinity of a bilayer membrane, some of the exposed peptides become inserted in the lipid bilayer (5-8) and are assembled into transmembrane channels (9-12).From measurements of the molecular ratios among the individual complement proteins in the membrane-associated complex, Kolb et aL (13) proposed the formula C5b1C6lC7lC8lC9n, with a maximal value of n = 6. Subsequently, Biesecker et al. (14) estimated from hydrodynamic analyses of detergent-extracted complexes that the molecular weight is 1.7 x 106. They concluded from this value that the complex is a dimer of C5b-9 and proposed the formula (C5b1C61C71C81C93)2.By contrast, Bhakdi and Tranum-Jensen proposed that the complex is a monomer of C5b-9. They drew attention to the polydispersity ofthe detergent-solubilized complexes as judged by electron microscopy, ultracentrifugation in density gradients, and gel exclusion chromatography (15). According to their results, the smallest complexes are monomers of C5b-9, which have the structural appearance of hollow cylinders apparently identical to the characteristic complement lesions seen on target membranes. Their heavier ultracentrifugal fractions contained aggregates of these cylinders.An important part of this disa...

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Increased ion permeability of planar lipid bilayer membranes after treatment with the C5b-9 cytolytic attack mechanism of complement.

Cited by 91 publications

References 23 publications

C3b deposition on human erythrocytes induces the formation of a membrane skeleton–linked protein complex

C3b deposition on human erythrocytes induces the formation of a membrane skeleton–linked protein complex

Terminal complement complex C5b-9 stimulates mitogenesis in 3T3 cells.

Transmembrane channel formation by complement: functional analysis of the number of C5b6, C7, C8, and C9 molecules required for a single channel.

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