References of "Vandekerckhove, J."
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See detailNeutralizing monoclonal antibodies can potentiate IL-5 signaling
Zabeau, L.; Van der Heyden, J.; Broekaert, D. et al

in European Journal of Immunology (2001), 31(4), 1087-97

IL-5 is a major determinant in the survival, differentiation and effector-functions of eosinophils. It mediates its effect upon binding and activation of a membrane bound receptor (R), composed of a ... [more ▼]

IL-5 is a major determinant in the survival, differentiation and effector-functions of eosinophils. It mediates its effect upon binding and activation of a membrane bound receptor (R), composed of a ligand-specific alpha-chain and a beta-chain, shared with the receptors for IL-3 and granulocyte-macrophage colony-stimulating factor. We have generated and mapped the epitopes of three monoclonal antibodies (mAb) directed against this cytokine: the strong neutralizing mAb 5A5 and 1E1, and the very weak neutralizing mAb H30. We found that H30 as well as 5A5 can increase proliferation above the level induced by human (h)IL-5 alone, in a JAK-2-dependent manner, and at every sub-optimal hIL-5 concentration analyzed. This effect is dependent on mAb-mediated cross-linking of IL-5R complexes, and is only observed on cell lines expressing a hybrid human/mouse IL-5Ralpha-chain. We discuss these findings in view of the stoichiometric and topological requirements for an activated IL-5R. Since humanized anti-IL-5 mAb are currently in clinical testing, our findings imply that such mAb should be carefully evaluated for their potentiating effects. [less ▲]

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See detailVillin function in the organization of the actin cytoskeleton. Correlation of in vivo effects to its biochemical activities in vitro.
Friederich, Evelyne UL; Vancompernolle, K.; Louvard, D. et al

in The Journal of biological chemistry (1999), 274(38), 26751-60

Villin is an actin-binding protein of the intestinal brush border that bundles, nucleates, caps, and severs actin in a Ca(2+)-dependent manner in vitro. Villin induces the growth of microvilli in ... [more ▼]

Villin is an actin-binding protein of the intestinal brush border that bundles, nucleates, caps, and severs actin in a Ca(2+)-dependent manner in vitro. Villin induces the growth of microvilli in transfected cells, an activity that requires a carboxyl-terminally located KKEK motif. By combining cell transfection and biochemical assays, we show that the capacity of villin to induce growth of microvilli in cells correlates with its ability to bundle F-actin in vitro but not with its nucleating activity. In agreement with its importance for microfilament bundling in cells, the KKEK motif of the carboxyl-terminal F-actin-binding site is crucial for bundling in vitro. In addition, substitutions of basic residues in a second site, located in the amino-terminal portion of villin, impaired its activity in cells and reduced its binding to F-actin in the absence of Ca(2+) as well as its bundling and severing activities in vitro. Altogether, these findings suggest that villin participates in the organization and stabilization of the brush border core bundle but does not initiate its assembly by nucleation of actin filaments. [less ▲]

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See detailConformational behaviour of a synthetic peptide of the C-terminus of villin that interacts with actin: an NMR, CD and stimulated annealing study.
Simenel, C.; Rose, T.; Goethals, M. et al

in International journal of peptide and protein research (1995), 45(6), 574-86

The solution structure of a synthetic 22-amino acid peptide (P1) corresponding to the extreme C-terminal end and one of the F-actin binding sites of villin has been determined by 1H NMR and CD ... [more ▼]

The solution structure of a synthetic 22-amino acid peptide (P1) corresponding to the extreme C-terminal end and one of the F-actin binding sites of villin has been determined by 1H NMR and CD spectroscopy. The structure of this peptide was compared to that of a peptide in which lysine to glutamic acid substitutions were introduced at positions 17 and 19 (P11), abolishing F-actin binding. Both peptides are largely unstructured in aqueous solution. Changes observed in the NMR and CD spectra of both peptides are consistent with alpha-helix formation in trifluoroethanol/water mixtures. A set of 189 interproton distances derived from nuclear Overhauser enhancement (NOE) measurements, 17 phi-angle constraints obtained from 3JNH alpha coupling constants, as well as about 10 N ... O distance restraints deduced from amide proton exchange kinetics with deuterium, were used for the structure determination. The three-dimensional structure of P1 and P11 is characterized by two helical regions, one extending from residues 2 to 5 and a second covering residues 7 to 17. The central fragment, ranging from Leu-7 to Leu-15, is more stable. The C-terminal residues are less structured, particularly within peptide P11. The significance of these structural results is discussed in relation to the biological activity of villin. [less ▲]

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See detailAn actin-binding site containing a conserved motif of charged amino acid residues is essential for the morphogenic effect of villin.
Friederich, Evelyne UL; Vancompernolle, K.; Huet, C. et al

in Cell (1992), 70(1), 81-92

The actin-binding protein villin induces microvillus growth and reorganization of the cytoskeleton in cells that do not normally produce this protein. Transfection of mutagenized villin cDNAs into CV-1 ... [more ▼]

The actin-binding protein villin induces microvillus growth and reorganization of the cytoskeleton in cells that do not normally produce this protein. Transfection of mutagenized villin cDNAs into CV-1 cells was used to show that a conserved, COOH-terminally located cluster of charged amino acid residues (KKEK) is crucial for the morphogenic activity of villin in vivo. In vitro experiments with a 22 amino acid synthetic peptide corresponding to this region of villin provide evidence that this motif is part of an F-actin-binding site that induces G-actin to polymerize. Chemical cross-linking of actin to this peptide, the effects of amino acid substitutions in peptides, and the behavior of villin variants further corroborate the participation of the KKEK sequence in actin contacts. [less ▲]

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