Simultaneous dissection and comparison of IL‐2 and IL‐15 signaling pathways by global quantitative phosphoproteomics

Abstract

Common γ-chain family of cytokines (IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21, where IL stands for interleukin) are key regulators of the immune homeostasis that exhibit pleiotropic biological activities and even sometimes redundant roles as a result of the utilization of the same receptor subunit. However, they also exert distinct functions that make each of them to be indispensable. For instance, all family members can act as T-cell growth factors; however, we found that IL-15 but not IL-7 can replace IL-2 to promote and sustain the proliferation of Kit225T cells. In addition to the γ-chain, IL-2 and IL-15 share the β-chain, which creates the paradox of how they can trigger diverse phenotypes despite signaling through the same receptors. To investigate this paradigm, we combined SILAC with enrichment of tyrosine-phosphorylated proteins and peptides followed by mass spectrometric analysis to quantitatively assess the signaling networks triggered downstream IL-2/IL-2R and IL-15/IL-15R. This study confirmed that the transduction pathways initiated by both cytokines are highly similar and revealed that the main signaling branches, JAK/STAT, RAS/MAPK and PI3K/AKT, were nearly equivalently activated in response to both ILs. Despite that, our study revealed that receptor internalization rates differ in IL-2- and IL-15-treated cells indicating a discrete modulation of cytokine signaling. All MS data have been deposited in the ProteomeXchange with identifier PXD001129 (http://proteomecentral.proteomexchange.org/dataset/PXD001129).

Nuclear Phosphoproteomic Screen Uncovers ACLY as Mediator of IL-2-induced Proliferation of CD4+ T lymphocytes

“…We and others have previously demonstrated that IL-2, or its closely related family member IL-15, is required for promoting the proliferation of Kit225 T cells (29,53). In the present study we aimed to investigate the role of ACLY in IL-2-mediated T-cell growth.…”

Mass spectrometry-based proteomic exploration of the human immune system: focus on the inflammasome, global protein secretion, and T cells

“…In these studies, Osinalde and co-workers utilized SILAC labeling and high resolution MS combined with phosphotyrosine immunoprecipitation [91][92][93] and TiO2 enrichment of the phosphopeptides [94,95] to demonstrate that the signaling pathways activated by IL-2 and IL-15 are very similar [94,95]. In addition, they combined antibody-and TiO2-based enrichment with SILAC labeling before MS analysis to show that serine/threonine phosphorylation of the scaffold protein Gab2 is an important step in regulating IL-2 signaling [96] Quantitative phosphoproteomics has also been used to characterize CD8+ CTLs in detail [97,98].…”

Nola eragiten du 2-Interleukinak T-zelulen nukleoko proteinen fosforilazio mailan?

“…Hain zuzen ere, aurreko lan batean sakon aztertu genituen zitokinak T-zeluletan sustatzen dituen seinalizazio-sareak IL-2ren eraginez fosforilatzen diren proteinak masa-espektrometria bidez aztertuz [20,21].…”

“…Emaitzak bat etorri ziren eskala handian egiten diren fosfoproteomika-esperimentuen emaitza ohikoekin [21,33,34,36] eta ikusi genuen, antzemandako aminoazido gehienen fosforilazio maila berdintsu mantentzen dela kitzikatutako zein kitzikatu gabeko T-zeluletan (4.irudia, puntu grisak). Halere, azpimarratu beharra dago ehunka aminoazidoren fosforilazio maila nabarmen aldatu zela IL-2rekin EKAIA, 32 (2017) Nerea Osinalde 3. irudia.…”