Structural similarities between the mammalian beta-adrenergic and reovirus type 3 receptors

The mechanism by which viruses bind to and infect specific tissues to cause disease has only recently begun to be understood. The mammalian reoviruses provide an especially attractive model for studying the details of cell surface recognition. The cell and tissue tropism of reovirus is determined by a portion of the viral hemagglutinin termed the neutralization domain. We have reported previously on the generation of both monoclonal and polyclonal anti-idiotypic antibodies that mimic the viral hemagglutinin in the specificity of binding to the reovirus receptor. By using these anti-idiotypic antibodies as specific probes, we have successfully isolated the mammalian reovirus receptor from neuronal and lymphoid cells. In the present study, we report that the reovirus receptor is structurally similar to the mammalian beta-adrenergic receptor. This conclusion is based on the following observations: (i) purified beta-adrenergic receptor is immunoprecipitable by anti-reovirus receptor antibody; (ii) purified reovirus receptor obtained from murine thymoma cells and beta-adrenergic receptor obtained from calf lung exhibit identical molecular masses and isoelectric points; (iii) trypsin digests of purified reovirus and beta-adrenergic receptors display indistinguishable fragment patterns; (iv) purified reovirus receptor binds the beta-antagonist [125I]iodohydroxybenzylpindolol and this binding is blocked by the beta-agonist isoproterenol.