Insulin-like Growth Factor I Receptor (IGF-IR) is a type 1 transmembrane protein that functions as a receptor for the insulin-like growth factors (IGFs) in cells. It is a member of the tyrosine kinase receptor family, meaning it activates intracellular signaling pathways through the phosphorylation of tyrosine residues.
IGF-IR plays a crucial role in mediating the biological actions of IGF-I and IGF-II, which are peptide growth factors involved in the regulation of cellular growth, proliferation, differentiation, and apoptosis. It is widely expressed in various tissues including skeletal muscle, liver, kidney, and brain.
Upon binding of IGF-I or IGF-II to the IGF-IR, the receptor undergoes autophosphorylation of specific tyrosine residues, leading to the activation of downstream signaling cascades, such as the PI3K/AKT and Ras/MAPK pathways. These pathways play a significant role in regulating cell survival, metabolism, and growth.
The activation of IGF-IR signaling has been implicated in various physiological and pathological processes, including development, tissue homeostasis, and cancer progression. Dysregulation of IGF-IR signaling has been observed in a variety of cancers, making it an attractive target for therapeutic interventions.
In summary, Insulin-like Growth Factor I Receptor is a transmembrane receptor that serves as a key mediator of the cellular responses to IGF-I and IGF-II. It plays a critical role in regulating cell growth, proliferation, and survival through intracellular signaling pathways.
