Distinct pathways involving the FK506-binding proteins 12 and 12.6 underlie IL-2- versus IL-15-mediated proliferation of T cells

Sigrid Dubois, Weinian Shou, Laura S. Haneline, Sidney Fleischer, Thomas A. Waldmann, Jürgen R. Müller

Research output: Contribution to journalArticle

32 Scopus citations


The molecular basis for the different roles of IL-2 and IL-15 in lymphocyte function has been poorly defined. Searching for differences that underlie the distinct T cell responses to the two cytokines, we observed a marked susceptibility of the IL-15-induced but not of the IL-2-induced proliferation to rapamycin despite a decrease of p70S6 kinase (p70 S6K) activation by the drug in response to both cytokines. Activated splenic T lymphocytes deficient in the FK506-binding protein (FKBP) 12, a target of rapamycin activity, had reduced proliferation in response to IL-15 but not to IL-2. This decreased proliferation was accompanied by reduced activation of p70S6K and of the extracellular signal-regulated kinases (ERK) after IL-15 treatment. In contrast to FKBP12-/- cells, splenic FKBP12.6-/- T cells exhibited a decreased proliferative response to IL-2 in the presence of rapamycin without affecting p70 S6K or ERK activation. Thus, IL-15 induces T cell proliferation mainly via FKBP12-mediated p70S6K activation. In contrast, IL-2 signaling involves multiple pathways that include at least one additional pathway that depends on FKBP12.6.

Original languageEnglish (US)
Pages (from-to)14169-14174
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue numberSUPPL. 2
StatePublished - Nov 25 2003


ASJC Scopus subject areas

  • General

Cite this