Interleukin 11
Interleukin 11 (IL-11) is a protein that in humans is encoded by the IL11 gene.
IL-11 is a multifunctional cytokine first isolated in 1990 from bone marrow-derived stromal cells. It is a key regulator of multiple events in hematopoiesis, most notably the stimulation of megakaryocyte maturation. It is also known under the names adipogenesis inhibitory factor (AGIF) and oprelvekin.
The human IL-11 gene, consisting of 5 exons and 4 introns, is located on chromosome 19, and encodes a 23 kDa protein. IL-11 is a member of the IL-6-type cytokine family, distinguished based on their use of the common co-receptor gp130. Signal specificity is provided by the IL-11Rα subunit.
Downstream signalling
Signal transduction is initiated upon binding of IL-11 to IL-11Ralpha and gp130, facilitating the homodimerization of gp130 molecules. This permits gp130-associated Janus kinases (JAK) to become activated and phosphorylate intracellular tyrosine residues on gp130.
Function
IL-11 has been demonstrated to improve platelet recovery after chemotherapy-induced thrombocytopenia, induce acute phase proteins, modulate antigen-antibody responses, participate in the regulation of bone cell proliferation and differentiation IL-11 causes bone-resorption. It stimulates the growth of certain lymphocytes and, in the murine model, stimulates an increase in the cortical thickness and strength of long bones. In addition to having lymphopoietic/hematopoietic and osteotrophic properties, it has functions in many other tissues, including the brain, gut, testis and bone.