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Calcium as a Potential Physiological Regulator of Integrin-Mediated Cell Adhesion

D Kirchhofer, J Grzesiak, M D Pierschbacher

J Biol Chem. 1991 Mar 5;266(7):4471-7.

PMID: 1705553

Abstract:

alpha v beta 1 and alpha v beta 3 are two related members of the integrin family of cell surface receptors both of which interact with their ligands through the Arg-Gly-Asp recognition sequence, alpha v beta 1 and alpha v beta 3 share the same cation-binding subunit, alpha v, suggesting a similar cation requirement for both integrins. Instead, we observed that Ca2+ exerts different effects on their binding function. The attachment of alpha v beta 3-loaded liposomes to vitronectin and the alpha v beta 3-mediated adhesion of U 251 cells to an Arg-Gly-Asp-containing peptide was supported equally well by Ca2+ and Mg2+. However, IMR 32 cells which bind to Arg-Gly-Asp-containing peptides through alpha v beta 1 adhered in Mg2+ but not in Ca2+. In agreement, Ca2+ did not support the attachment of alpha v beta 1-loaded liposomes to the macromolecular ligand fibronectin or the binding of alpha v beta 1 to Gly-Arg-Gly-Asp-Ser-Pro-Lys-Sepharose in affinity chromatography experiments. Furthermore, in the presence of a constant Mg2+ concentration, Ca2+ had opposite effects on the two receptors in that it inhibited the alpha v beta 1-mediated adhesion of IMR 32 cells to the peptide substrate while enhancing alpha v beta 3-mediated adhesion of U251 cells. The Ca2+ effects occurred at physiological cation concentrations and therefore, our data suggest a physiological role for Ca2+ as a regulator of integrin function and indicate a possible involvement of the beta subunits in cation binding.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP111119289 Gly-Arg-Gly-Asp-Ser-Pro-Lys Gly-Arg-Gly-Asp-Ser-Pro-Lys 111119-28-9 Price
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