Binding of interleukin 2 to its 75-kDa intermediate affinity receptor is sufficient to activate Na+/H+ exchange

G. B. Mills, C. May

    Research output: Contribution to journalArticle

    16 Scopus citations

    Abstract

    High affinity interleukin 2 (IL-2) binding sites are composed of two IL-2 binding molecules: one of 55 kDa, commonly called TaC, and another of 75 kDa. In the absence of the other IL-2-binding molecule, the 55-kDa molecule binds IL-2 with a relatively low affinity and the 75 kDa molecule binds IL-2 with an intermediate affinity. One of the earliest events following interaction of IL-2 with its receptor on the surface of cells is an increase in intracellular pH due to activation of the Na+/H+ antiport. In contrast to IL-2 induced proliferation of human IL-2-sensitive T cells, interaction of IL-2 with a low affinity binding site was sufficient to activate the Na+/H+ antiport. By determining the effect of IL-2 on cytosolic pH in cells that express one of the two IL-2-binding molecules in the absence of the other IL-2-binding molecule, we have demonstrated that interaction of IL-2 with the 75 kDa IL-2 binding molecule is sufficient to activate the Na+/H+ antiport and thus induce cytosolic alkalinization. This indicates that the 75-kDa IL-2-binding molecule, in the absence of the 55-kDa IL-2-binding molecule, forms a functional receptor that can transduce an activation signal across the cell membrane.

    Original languageEnglish (US)
    Pages (from-to)4083-4087
    Number of pages5
    JournalJournal of Immunology
    Volume139
    Issue number12
    StatePublished - Dec 1 1987

    ASJC Scopus subject areas

    • Immunology and Allergy
    • Immunology

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