Definition of the EGTA-independent interface involved in the serum gelsolin-actin complex

Feinberg, Jeanne; Capony, Jean‐Paul; Benyamin, Yves; Roustan, Claude

doi:10.1042/bj2930813

Cited by 10 publications

(4 citation statements)

References 43 publications

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“…Bovine plasma gelsolin was purified as described by Soua et al [20]. Domain 1 was obtained by chymotryptic cleavage of gelsolin and purified as previously described [21]. CapZ was purified from fish muscle (unpublished data).…”

Section: Proteins and Peptidesmentioning

confidence: 99%

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Capping and dynamic relation between domains 1 and 2 of gelsolin

et al. 1998

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Gelsolin is a protein that severs and caps actin filaments. The two activities are located in the N-terminal half of the gelsolin molecules. Severing and subsequent capping requires the binding of domains 2 and 3 (S2-3) to the side of the filaments to position the N-terminal domain 1 (S1) at the barbed end of actin (actin subdomains 1 and 3). The results provide a structural basis for the gelsolin capping mechanism. The effects of a synthetic peptide derived from the sequence of a binding site located in gelsolin S2 on actin properties have been studied. CD and IR spectra indicate that this peptide presented a secondary structure in solution which would be similar to that expected for the native full length gelsolin molecule. The binding of the synthetic peptide induces conformational changes in actin subdomain 1 and actin oligomerization. An increase in the polymerization rate was observed, which could be attributed to a nucleation kinetics effect. The combined effects of two gelsolin fragments, the synthetic peptide derived from an S2 sequence and the purified segment 1 (S1), were also investigated as a molecule model. The two fragments induced nucleation enhancement and inhibited actin depolymerization, two characteristic properties of capping. In conclusion, for the first time it is reported that the binding of a small synthetic fragment is sufficient to promote efficient capping by S1 at the barbed end of actin filaments.

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Section: Proteins and Peptidesmentioning

confidence: 99%

“…Peptide 159±174 was labelled at the amino groups with 7-chloro-4-nitroso-2-oxo-1.3 diazole (NbdCI) [21]. Excess reagent was eliminated by sieving through a Biogel P2 column.…”

Section: Proteins and Peptidesmentioning

confidence: 99%

Capping and dynamic relation between domains 1 and 2 of gelsolin

et al. 1998

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“…In the absence of calcium, gelsolin cannot bind actin as its three [5,16] identified actin binding sites residing in G1, G2 and G4 [7,16,17] are not accessible. In the presence of calcium, gelsolin becomes activated by the unfolding of the whole molecule so that the F‐actin binding region in G2 is exposed allowing the molecule to make the initial contact with the actin filament.…”

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confidence: 99%

Co‐operation of domain‐binding and calcium‐binding sites in the activation of gelsolin

Lagarrigue

Maciver

Fattoum

et al. 2003

European Journal of Biochemistry

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Gelsolin is an abundant calcium dependent actin filament severing and capping protein. In the absence of calcium the molecule is compact but in the presence of calcium, as its six similar domains alter their relative position, a generally more open configuration is adopted to reveal the three actin binding sites. It is generally held that a Ôhelical-latchÕ at the C-terminus of gelsolin's domain 6 (G6), binds domain 2 (G2) to keep gelsolin in the calcium-free compact state, and that the crutial calcium binding site(s) reside in the C-terminal half of gelsolin perhaps involving the C-terminal helix itself has to be bound to release this latch. Here we provide evidence for a calcium dependent conformational change within G2 (K d ¼ 15 lM). We also report a calcium dependent binding site for the C-terminus (G4-6) within G2 and delimit this further to a specific region formed by residues 203-225 and 159-193. It is known that the activation of gelsolin involves multiple calcium binding events (around 6) the first of which (in G6) may release the latch. We propose that the calcium-dependent conformational change in G2 may be a subsequent step that is necessary for the dissociation of G2 from G4-6, and that this movement occurs in sympathy with calcium induced conformational changes within G6 by the physical coupling of the two calcium binding sites within G2 and G6. Additional calcium binding in other domains then result in the complete opening and activation of the gelsolin molecule.

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“…Gelsolin is composed of six of these similarly folded repeats (G1–6) that in the absence of calcium wrap around each other forming a compact globular protein [2]. In this compact state, gelsolin's actin binding sites primarily residing in G1, G2, G4 and G6 [3–5] are inaccessible. Gelsolin becomes activated in the presence of calcium, by both inter and intra‐domain movement through a poorly understood mechanism that results in the F‐actin binding region in G2 making the initial contact with the actin filament.…”

Section: Introductionmentioning

confidence: 99%

Calcium‐induced conformational changes in the amino‐terminal half of gelsolin

Roustan¹,

Ferjani²,

Maciver³

et al. 2007

FEBS Letters

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Gelsolin is an actin-binding protein that is regulated by the occupancy of multiple calcium-binding sites. We have studied calcium induced conformational changes in the G1-2 and G1-3 sub-domains, and report the binding affinities for the three type II sites. A new probe for G3 has been produced and a K d of 5 lM has been measured for calcium in the context of G1-3. The two halves of gelsolin, G1-3 and G4-6 bind weakly with or without calcium, suggesting that once separated by apoptotic proteolysis, G1-3 and G4-6 remain apart allowing G1-3 to sever actin in a calcium free manner.

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Definition of the EGTA-independent interface involved in the serum gelsolin-actin complex

Cited by 10 publications

References 43 publications

Capping and dynamic relation between domains 1 and 2 of gelsolin

Capping and dynamic relation between domains 1 and 2 of gelsolin

Co‐operation of domain‐binding and calcium‐binding sites in the activation of gelsolin

Calcium‐induced conformational changes in the amino‐terminal half of gelsolin

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