SOCS3, a Major Regulator of Infection and Inflammation

Abstract

In this review, we describe the role of suppressor of cytokine signaling-3 (SOCS3) in modulating the outcome of infections and autoimmune diseases as well as the underlying mechanisms. SOCS3 regulates cytokine or hormone signaling usually preventing, but in some cases aggravating, a variety of diseases. A main role of SOCS3 results from its binding to both the JAK kinase and the cytokine receptor, which results in the inhibition of STAT3 activation. Available data also indicate that SOCS3 can regulate signaling via other STATs than STAT3 and also controls cellular pathways unrelated to STAT activation. SOCS3 might either act directly by hampering JAK activation or by mediating the ubiquitination and subsequent proteasome degradation of the cytokine/growth factor/hormone receptor. Inflammation and infection stimulate SOCS3 expression in different myeloid and lymphoid cell populations as well as in diverse non-hematopoietic cells. The accumulated data suggest a relevant program coordinated by SOCS3 in different cell populations, devoted to the control of immune homeostasis in physiological and pathological conditions such as infection and autoimmunity.

Keywords: IL-6; JAK; SOCS; STAT; STAT3; autoimmunity; cytokine; infection.

Figure 1

Simultaneous binding of SOCS3 to JAK and the gp130 cytokine receptor. Adapted from Ref. (56).

Figure 2

Role of SOCS3 in the control of infection. (A) During M. tuberculosis and T. gondii infection, SOCS3 is induced in macrophages and DCs prevents the IL-6-mediated inhibition of IL-12 secretion, promoting a CD4+ cell-dependent IFN-γ expression. (B) SOCS3 controls the development of γδ+ T cells. Such control is critical for proper protection against M. tuberculosis.