A study on the structure and interactions of the C1 sub-components C1r and C1s in the fluid phase

Arlaud, Gérard J.; Chesne, Serge; Villiers, Christian; Colomb, Maurice G.

doi:10.1016/0005-2744(80)90268-5

Cited by 37 publications

(38 citation statements)

References 26 publications

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“…These kinetic data are likely to reveal additional information on Cl structure to results obtained by surface iodination [25,26]. They also indicate that for a physiological concentration of C2 (1.2 X lob7 M, [28]) cleavage of C2 is probably very inefficient unless C2 is 'presented' to Ci in an optimal position defined by C4b.…”

Section: Discussionmentioning

confidence: 78%

“…Electrophoresis was done as in section 2: 18 pg protein were applied to each gel -(1) unreduced C2; (2) reduced and alkylated C2. showed that in both cases Cis was entirely incorporated in a ci;,-Cis2 tetrameric association, as in [25]. The association of Cir with Cis induces a slight decrease of Kn, and V, of the reaction ( fig.3, table 2).…”

Section: Affinity Chromatography On C4b-sepharosementioning

confidence: 78%

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Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r₂–C1̄s₂ AND 1̄

et al. 1982

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Section: Discussionmentioning

confidence: 78%

Section: Affinity Chromatography On C4b-sepharosementioning

confidence: 78%

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r₂–C1̄s₂ AND 1̄

et al. 1982

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“…140 pI of the supernatant was added to 40 pl of 0.4 M EDTA and incubated for 40 min at 37°C in order to allow C l r and C l s to activate. The C l s esterolytic activity was measured on 100 p1 aliquots of the mixture using tosyl arginine methyl ester as substrate [29]. All media used for C1 dissociation contained 5 mM CaCI,/10 mM Tris/HCl (pH 7.4), and the ionic strength was adjusted at 0.13 by addition of NaCl.…”

Section: Prrparnrion (~F Ig-orwlhunirn -C L Complexes Und Treutnientmentioning

confidence: 99%

“…140 p1 of the supernatant was added to 40 p1 of0.4 M EDTA arid incubated 40 min at 37 "C in order to allow C l r and CIS activation. The CTs esterolytic activity was measured on 100-p1 aliquots ofthe incubation medium using tosyl arginine methyl ester as substrate [29]. c'l dissociation was achieved with 5 mM CaCI,, glutamine or p-aminophenylalanine were not able to dissociate Clr,-Cls, from C l q (Table 1).…”

Section: Influence Of Polyamine Structure On C L Dissociationmentioning

confidence: 99%

Diamine-induced dissociation of the first component of human complement, C1

1984

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Lysine has been shown to inhibit spontaneous and antibody-dependent C1 activation. This paper demonstrates that lysine does not prevent autoactivation of purified Clr. 20 mM lysine, 1,2-diaminoethane, 1,3-diaminopropane, 1,Cdiaminobutane or 1,5-diaminopentane are able to dissociate C1 into its two entities, C l q and the calciumdependent Clr,-Cls, complex. Ig-ovalbumin insoluble complexes bearing C1 are also dissociated by lysine and the above-mentioned diamines used at the same concentration: Clq remains bound to the immune complexes whereas the Clr,-Cls, complex is partially solubilized.The effect of lysine or diamines is not due to a competition with calcium for calcium-binding sites, as increasing concentrations of calcium even slightly increase the dissociation due to the amines.The dissociative effect is dependent on the carbon chain length of the diamines, with an optimum for 1,3-diaminopropane. It is also dependent on the relative 'cis-position' of the amino groups in the diamines. Polyamines such as spermine and spermidine are also able to dissociate C1 with even a higher efficiency than lysine and putrescine.Thus, a diamine-induced 'structural inhibition' of C1 is demonstrated, of potential interest for a pharmacological control of complement activation.The complement system contributes to the non-specific immune defence of the organism, as it can be triggered by different stimuli such as immune complexes, polyanions, bacterial or viral membranes, exogenous proteases [l 1. Activation of the system can proceed by two different pathways, the classical and the alternative pathway, and consists of a cascade of proteolytic reactions. Biological effects such as cytolysis or inflammation are the most evident expression of the activation.Activation of the classical pathway implies, as a primary event, the activation of C1, a calcium-dependent complex of three different proteins, Clq, C l r and Cls. The structure of C1 is now relatively well known and appears to consist of two entities: a tight Clr,-Cls2 complex, in loose association with Clq, under physiological conditions [2 -71. The activation of C1 proceeds through a sequential activation of C l r and CIS in which the initial autoactivation of C l r appears the most meaningful event. The autocatalytic potential is expressed in purified C l r itself, which is able to autoactivate upon incubation at 37 "C, in the presence of EDTA [8 -lo]. Inside C1, this autocatalytic potential is modulated by the association with the two other subcomponents: Cls and Clq, as the activation energy for C1 activation [Ill is lower than the activationenergy for C l r activation [8]. Incontrast, in the ClrNomenclature and Abbreviations. The nomenclature of complement components is that recommended by the World Health Organization [20] ; activated components are indicated by an overbar. SDS, sodium dodecyl sulphate; cadaverine, 1 $diaminopentane ; putrescine, 1 .Cdiaminobutane ; spermidine, W(3-aminopropyl)-1,4-diaminobutane ; spermine, N,N'-bis(3 aminopropy1)-I ,4-diaminobutane; a...

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“…In addition, this binding results in a dimerization of C)-s monomer [9]. The effect of Ca 2+ on the electrophoretic mobilities of C]-s as well as fragment 1 and fragment 2, observed here, suggests that certain conformational changes may be induced in these proteins by the binding of Ca 2+ and these changes may cause dimerization of these proteins as well as the development of the ability in them to bind to C]-r. In [10], Cls monomer and C]-r dimer interacted even in the absence of Ca z+ to form a CTr2-CTs complex, whereas in the presence of Ca 2+, the two subcomponents were associated into a C]~r2-C]-s2 complex. Therefore, it is also probable that fragment 1 and 2 interact with Clr even in the absence of Ca 2+.…”

Section: Discussionmentioning

confidence: 99%

Studies on the Cr‐binding site of rabbit Cs by plasmin fragmentation

et al. 1981

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A study on the structure and interactions of the C1 sub-components C1r and C1s in the fluid phase

Cited by 37 publications

References 26 publications

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r₂–C1̄s₂ AND 1̄

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r₂–C1̄s₂ AND 1̄

Diamine-induced dissociation of the first component of human complement, C1

Studies on the Cr‐binding site of rabbit Cs by plasmin fragmentation

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A study on the structure and interactions of the C1 sub-components C1r and C1s in the fluid phase

Cited by 37 publications

References 26 publications

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r2–C1̄s2 AND 1̄

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r2–C1̄s2 AND 1̄

Diamine-induced dissociation of the first component of human complement, C1

Studies on the Cr‐binding site of rabbit Cs by plasmin fragmentation

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Product

Resources

About

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r₂–C1̄s₂ AND 1̄

Human complement subcomponent C2: purification and proteolytic cleavage in fluid phase by C1̄s, C1̄r₂–C1̄s₂ AND 1̄