title: Evidence for sodium metasilicate receptors on the human osteoblast cell surface; spatial localization and binding properties.
abstract: We report details of the interaction of sodium metasilicate with osteoblast cellular membranes using Fluoresceinphosphatidylethanolamine (FPE) as a fluorescent indicator of membrane interactions. Fluorescence imaging studies of the FPE-based indicator system revealed areas of localized binding that would be consistent with the presence of a structure with 'receptor-like' properties. From these results, it seems unlikely that silica binds 'non-specifically' to the osteoblast surface. Moreover, the receptors are localized into membrane domains. Such regions of the cell membrane could well be structures such as 'rafts' or other such localized domains within the membrane. The binding profile of silica with the osteoblast cell surface takes place with all the characteristics of a receptor-mediated process best represented by a cooperativity (sigmoidal) binding model with a Hill coefficient of 3.6.
authors.affiliation: Cell Biophysics Group, Institute of Biophysics, Imaging and Optical Science (IBIOS), School of Life Sciences, University of Nottingham , Nottingham , UK.
authors.forename: Kelly-Ann
authors.initials: KA
authors.lastname: Vere
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Richens
authors.forename: Jordan S
authors.initials: JS
authors.lastname: Lane
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Harris
authors.forename: James
authors.initials: J
authors.lastname: Duggan
authors.forename: Paul
authors.initials: P
authors.lastname: O'Shea
mesh_terms: D001665:Binding Sites; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D010006:Osteoblasts / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017640:Silicates / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D008565:Membrane Proteins; D017640:Silicates; C025349:sodium metasilicate