Characterization of receptor-associated protein complex assembly in Interleukin (IL)-2- and IL-15-activated T-lymphocytes

ABSTRACT: Despite extensive investigation, it remains a paradox that IL-2 and IL-15 can differentially modulate the immune response using the same signaling receptors. In our previous work, we dissected the phosphotyrosine-driven signaling cascades triggered by both cytokines in Kit225 T-cells unveiling subtle differences that may contribute to their functional dichotomy. In the present study, we aimed to decipher the receptor complex assembly in IL-2- and IL-15-activated T-lymphocytes that is fine tune orchestrated by site-specific phosphorylation events. Comparing the cytokine-induced interactome of the interleukin receptor beta and gamma subunits shared by the two cytokines, we defined the components of the early IL-2 and IL-15 receptor-associated complex discovering novel constituents such as FAM59A and SOCS2. Additionally, phosphopeptide-directed analysis allowed us to detect several cytokine-dependent and –independent phosphorylation events within the activated receptor complex including novel phosphorylated sites located in the cytoplasmic region of IL-2Rβ. We proved that the distinct phosphorylations induced by the cytokines serve for recruiting different types of effectors to the initial receptor/ligand complex. Whereas IL-2Rβ pS431 binds to clathrins, which are involved in the receptor internalization and subsequent signal attenuation, IL-2Rγ pY325 and pY357 attract phosphatases, adaptor proteins, kinases as well as the newly identified member of the interleukin receptor complex SOCS2. Overall our study sheds new light into the initial molecular mechanisms triggered by IL-2 and IL-15 and constitutes a further step towards a better understanding of the early signaling aspects of the two closely-related cytokines in T-lymphocytes.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Suspension Culture, T Cell

SUBMITTER: Nerea Osinalde  

LAB HEAD: Irina Kratchmarova

PROVIDER: PXD002386 | Pride | 2016-08-08

REPOSITORIES: Pride