The IL-15Rα chain signals through association with Syk in human B cells

E. Bulanova, V. Budagian, T. Pohl, H. Krause, H. Dürkop, R. Paus, S. Bulfone-Paus

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


The α-chain of the IL-15R (IL-15Rα) serves as the specific, high-affinity receptor for IL-15. It is expressed by lymphoid and nonlymphoid cells, including B cell lymphoma lines. In this study, we have further explored IL-15Rα-mediated signaling in activated primary B cells and in Raji cells, a human B-lymphoblastoid cell line which expresses the IL-15Rα and IL-2Rγ chains, but lacks the IL-2Rβ chain. Stimulation of Raji cells with IL-15 induces their proliferation and rescues them from C2-ceramide-induced apoptosis. By immunoprecipitation and Western blotting, we show that treatment of Raji cells and activated primary B cells with IL-15 induces coprecipitation of Syk kinase with the IL-15Rα chain. Upon association, the activated Syk kinase phosphorylates the IL-15Rα chain as well as phospholipase Cγ, which coprecipitates with Syk. Furthermore, transfection of Raji cells with stem-loop Syk antisense oligonucleotides prevents IL-15Rα and phospholipase Cγ phosphorylation as well as the inhibition of apoptosis by IL-15. Mutation of a defined region of the intracellular signaling portion of IL-15Rα (Tyr227) abrogates both the IL-15Rα/Syk association and IL-15Rα phosphorylation. Taken together, this suggests that Syk kinase physically and functionally associates with the IL-15Rα chain in B cells and that Syk plays a key role in mediating IL-15-induced signal transduction, thus accounting for the distinct functional consequences of IL-15 vs IL-2 binding to B cells.

Original languageEnglish (US)
Pages (from-to)6292-6302
Number of pages11
JournalJournal of Immunology
Issue number11
StatePublished - Dec 1 2001
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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