Growth Hormone Receptor (hGH binding protein), soluble

The somatotropin receptor (GHR) is the protein in the cell membrane of vertebrates to which the hormone somatropin (somatotropin, STH, GH), a growth factor, binds. The receptor belongs to the cytokine receptors. Its main actions are activation of a JAK-STAT signaling pathway, expression of insulin-like growth factor 1, and binding to the tyrosine kinase-coupled receptors SHP-2, which cause overall and length growth and fat loss in the body during the growth phase. Mutations in the GHR gene can lead to somatropin resistance and this can lead to a form of short stature called Laron syndrome. GHR in humans is produced primarily in liver and skeletal muscle. Three of the four GHR isoforms are transmembrane receptors, and the soluble isoform is called somatropin-binding protein (GHBP) . It lacks the cytoplasmic domain, and by reversible binding to somatropin, it functions as a buffer for this hormone in blood plasma.