Interaction and Functional Interference of Glucocorticoid Receptor and SOCS1

Abstract

Cytokine and glucocorticoid (GC) hormone signaling act in an integrated fashion to control inflammation and immune response. Here we establish a new mode of interaction of these two pathways and propose Suppressor of Cytokine Signaling (SOCS)-1 as an essential player in mediating cross-talk. We observed that glucocorticoid receptor (GR) and SOCS1 form an intracellular complex through an interaction, which required the SH2 domain of SOCS1 and the ligand binding domain of GR. Furthermore, GC stimulation was found to increase the nuclear level of SOCS1. SOCS1 binding to the GR did not require ligand binding of the receptor; however, it was abolished after long term GC stimulation, suggesting a functional role of the interaction for the early phase of GC action. The interaction between GR and SOCS1 appeared to negatively influence the transcription of the two GR-regulated genes, FKBP5 and MKP1, because the GC-dependent expression of these genes was inhibited by the SOCS1 inducer IFN␥ and enhanced in SOCS1-deficient murine embryonic fibroblasts as compared with IFN␥ treated wild-type cells. Our results suggest a prominent role of SOCS1 in the early phase of cross-talk between GR and cytokine signaling.Key principles determining the cellular response to cytokine signaling are duration of stimulus, prevalence of inhibitory feedback mechanisms, and operation of cross-talk with other cellular pathways. All of these factors interact to influence the strength and the quality of the physiological response. For cytokines operating via the Janus kinase (JAK) 2 /signal transducers and activators of transcription (STAT) pathway, both suppressor of cytokine signaling (SOCS) proteins and the glucocorticoid receptor (GR) have been identified as important intracellular regulators in this respect.SOCS proteins have been shown to serve both as feedback inhibitors as well as mediators of cross-talk with other signaling pathways. They comprise a family of 8 members, initially described as negative feedback regulators of the JAK/STAT pathway. All SOCS proteins share two functional domains: an SH2 domain, which primarily enables binding of phosphorylated tyrosine residues, and a C-terminal SOCS box, which serves as a recruiting site for ubiquitin ligases, thereby combining specific inhibition of JAK catalytic activity with generic mechanisms such as competition over binding sites and targeting of associated proteins to proteasomal degradation (1, 2).Recent evidence suggests that the negative regulatory function of SOCS is not restricted to the JAK/STAT pathway. Through interaction with other signaling intermediates SOCS proteins can interfere with crucial signaling pathways such as the NF-B and insulin receptor signaling pathways (3). Furthermore glucocorticoids (GC) can also influence cytokine signaling. They act together with cytokines in an integrated fashion to control inflammation, immune response, and other more diverse physiological functions in mammals (4). The effect of GCs is mediated by the GR, a member of the nuclear receptor...

Suppressor of Cytokine Signaling (SOCS)1 Regulates Interleukin-4 (IL-4)-activated Insulin Receptor Substrate (IRS)-2 Tyrosine Phosphorylation in Monocytes and Macrophages via the Proteasome

“…Induction of SOCS Family Member in Response to IL-4 and IL-13 Stimulation-Previous studies found that the SOCS family of proteins is critical for regulating M2 development (42,43,45,48,49) and IRS-1 signaling in response to insulin (47,50,51). Based on our findings that IL-4-induced IRS-2 signaling is rapidly turned on within 30 min and turned off by 180 min, we sought to define whether SOCS family members are involved in this negative regulatory process.…”

MMTV-neu mice deficient in STAT1 are susceptible to develop ovarian teratomas

“…Proteins from total cell extracts were separated on 8% SDS-PAGE and immunoreactive bands detected and quantified by Odyssey Infrared Imaging (LICOR, Biosciences) as described (Haffner et al, 2008). STAT1 immunohistochemistry was performed on paraffin-embedded sections with SC-346 antibody (Santa Cruz Biotechnology; 1:1000, 1hr R.T.) and the Rabbit-on-Rodent HRP-Polymer (Biocare Medical) as a secondary detection system.…”

Prognoses of patients with acute-on-chronic hepatitis B liver failure are closely associated with altered SOCS1 mRNA expression and cytokine production following glucocorticoid treatment

“…Haffner et al 22 observed that glucocorticoid receptor and SOCS1 form an intracellular complex by immunoprecipitation and appeared to increase the nuclear expression level of SOCS1. Cortisol treatment significantly elevated SOCS1 mRNA transcript levels in rainbow trout liver.…”

“…[18][19][20][21] Glucocorticoids suppresses inflammation by controlling and preventing the immune-correlated damages. The upregulation of SOCS1 by corticosteroids has been established both in vivo and in vitro, [22][23][24] which suggests that cortisol may be playing a key role in suppressing cytokine signaling and the associated inflammatory response through SOCS1. However, the effect of glucocorticoid on SOCS1 remains unclear in ACHBLF.…”