T cell growth factor receptor, also known as interleukin-2 receptor (IL-2R), is a protein receptor found on the surface of T cells that is involved in their growth and activation. It is a cell surface receptor that binds to interleukin-2 (IL-2), a cytokine produced by activated T cells, and transduces the signal to the interior of the cell.
The T cell growth factor receptor is composed of three polypeptide chains: alpha (CD25), beta (CD122), and gamma (CD132). The alpha subunit has a high affinity for IL-2, while the beta and gamma subunits are required for signal transduction. The receptor is expressed on the surface of activated T cells and plays a crucial role in T cell proliferation, survival, and immune response regulation.
Upon binding with IL-2, the T cell growth factor receptor activates several intracellular signaling pathways, including the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. This leads to the activation of various transcription factors, such as STAT3 and STAT5, which regulate the expression of genes involved in T cell proliferation and survival.
Defects in the T cell growth factor receptor or its signaling pathway can lead to immune dysregulation and impaired T cell function. For example, mutations in the IL-2R gamma subunit can cause X-linked severe combined immunodeficiency (X-SCID), a severe primary immunodeficiency disorder characterized by the absence of functional T and natural killer (NK) cells. Additionally, IL-2R signaling has been implicated in autoimmune diseases and cancer due to its role in regulating T cell activity.
