Description
Glycoprotein 130 (gp130), also known as IL6ST, IL6β and CD130), is a transmembrane protein and belongs to the class I cytokine receptor family. It is often referred to as the common gp130 subunit, shared by the functional receptor complexes of IL-6, IL-11, leukemia inhibitory factor (LIF), granulocyte colonystimulating factor, ciliary neurotrophic factor and cardiotrophin-1 (1). gp130 binds to IL-6/IL-6Rα complex, resulting in the formation of high-affinity IL-6 binding sites. This complex of three proteins then homodimerizes to form a hexameric complex which can produce downstream signals. gp130 signals are mediated by tyrosine kinases of the JAK family and by their binding partners, transcription factors of the STAT family (2). In addition, gp130 signaling is very important for osteoblast function and calcium homeostasis (3). gp130 is found in tissues such as brain, heart, thymus, spleen, kidney, lung and liver. It is involved in various human diseases, such as liver disease, coronary artery disease and myocardial infarction. Furthermore, gp130 is widely expressed in breast cancer cell lines and primary tumors, thus it has been implicated in constitutive STAT3 activation in breast cancer (4). Knockout studies in mice suggested a critical role of gp130 as the mice develop a broad spectrum of hematopoietic abnormalities, including splenomegaly, lymphadenopathy and thrombocytosis