The binding of ligands to the 55 kDa component of the interleukin-2 receptor triggers increased turnover of phosphate bound to an 85 kDa protein. Evidence for the role of cyclic AMP.
The cell-surface receptor for interleukin-2 (IL-2) consists of two unlinked polypeptides of 55 and 75 kDa (p55, p75). The monoclonal antibody antiTac binds to p55 alone. We show here that the binding of either IL-2 or antiTac to the surface of T lymphocytes triggered the generation of cAMP. Reagents which activate adenyl cyclase by stimulation of its guanine nucleotide-binding protein (Gs) also stimulated increases in cAMP. All of the above reagents, and cAMP itself, stimulated the turnover of phosphate residues bound to serine and threonine residues of an 85 kDa protein. The data provide evidence that the binding of ligands to the p55 component of the IL-2 receptor generates a biochemical signal by the stimulation of adenyl cyclase via Gs, and that the consequent generation of cAMP and activation of cAMP-dependent protein kinase modulates the turnover of p85-bound phosphate groups.
Mire-Sluis
A R
AR
Department of Haematology, Royal Free Hospital and School of Medicine, London, England.
Hoffbrand
A V
AV
Wickremasinghe
R G
RG
D000242:Cyclic AMP / Q000097:blood / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000097:blood*; D008024:Ligands / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000097:blood*; D008970:Molecular Weight; D010766:Phosphorylation; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D007376:Interleukin-2; D008024:Ligands; D008562:Membrane Glycoproteins; D015375:Receptors, Interleukin-2; D000242:Cyclic AMP