The interleukin (IL)-6 family of cytokines is defined by the shared use of the common signal transducing receptor gp130 beta-subunit. This family includes structurally and functionally related IL-6, IL-11, Leukemia inhibitory factor (LIF), oncostatin M (OSM) cardiotrophin-1 (CTF1) and Cardiotrophin-like cytokine factor 1 (CLCF1) (Taga & Kishimoto 1999, Taga 1996, Kishimoto et al. 1995). The sharing of gp130 explains at least in part the redundancy of the actions of these cytokines. The cytokines IL-6 and IL-11 bind to their corresponding receptors IL-6R and IL-11R, respectively, resulting in complex formations, which associate with gp130, leading to gp130-homodimer formation and signal initiation. LIF, CNTF, OSM, CTF1, CRLF1 , and CLCF1, signal via gp130/LIF-R heterodimeric receptor complexes (Taga & Kishimoto 1997, mousa & Bakhiet 2013). OSM also signals via a receptor complex consisting of gp130 and OSMR. These cytokines play an important role in the regulation of complex cellular processes such as gene activation, proliferation and differentiation (Heinrich et al. 1998). Although each member of the IL-6 family signals through the distinct receptor complex, the underlying signaling mechanism is similar in each case: the first event after cytokine stimulation is assembly of receptor complexes, the activation of receptor-associated kinases of the janus kinase (JAK) family then follows. Activation of JAK kinases is the pivotal step to initiate downstream cytoplasmic signaling cascades involving recruitment and phosphorylation of transcription factors of the signal transducer and activator of transcription (STAT) family, which dimerize, translocate to the nucleus, and bind to enhancer elements of respective target genes leading to transcriptional activation (Nakashima & Taga 1998)

external resources

CBL , CNTF , CNTFR , CTF1 , IL6 , IL6R , IL6ST , IL11 , IL11RA , IL12A , IL12RB2 , JAK1 , JAK2 , LIF , LIFR , OSM , PTPN11 , STAT1 , STAT3 , TYK2 , SOCS3 , OSMR , CRLF1 , IL27RA , EBI3 , CLCF1 , IL27 ,