Effect of selenite on cell surface fibronectin receptor.
Incubation of cells with selenite, under conditions in which there is no effect on cell viability, results in a decrease in the rate of their subsequent attachment to extracellular matrix proteins such as fibronectin (1). The attachment was inhibited by a pentapeptide containing the RGD sequence and by antibody against the cellular fibronectin receptor (alpha 5 beta 1 integrin), indicating that it is receptor-mediated. To investigate whether exposure to selenite has an effect on fibronectin receptors, we assayed for their presence on the cell surface by measuring the ability of cells to attach to a surface that had been coated with antibodies to the receptor. Brief exposure of cells to low concentrations of selenite resulted in a significant decrease in their ability to attach to monoclonal antibodies against the alpha 5 or beta 1 subunits of the fibronectin receptor, as well as to polyclonal antibodies against the complete receptor. This indicates that exposure to selenite results in a decrease in receptors that are present at the cell surface. Exposure of the cells to selenate, selenocystine or selenomethionine did not result in a significant decrease in cell surface receptors. Preincubation of the cells with selenite was required for the effect, indicating that selenite does not directly interfere with receptor structure or function.
Yan
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Department of Biological Sciences, Rutgers University, Newark, NJ 07102.
Frenkel
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GD
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D000939:Epitopes / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis; D011956:Receptors, Cell Surface / Q000187:drug effects* / Q000378:metabolism; D017469:Receptors, Fibronectin / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D018038:Sodium Selenite / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D005353:Fibronectins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D017469:Receptors, Fibronectin; D018038:Sodium Selenite