the interleukin 2 receptor, which is involved in t cell-mediated immune responses, is present in 3 forms with respect to ability to bind interleukin 2. the low affinity form is a monomer of the alpha subunit (also called cd25) and is not involved in signal transduction. the intermediate affinity form consists of a gamma/beta subunit heterodimer, while the high affinity form consists of an alpha/beta/gamma subunit heterotrimer. both the intermediate and high affinity forms of the receptor are involved in receptor-mediated endocytosis and transduction of mitogenic signals from interleukin 2. the protein encoded by this gene represents the beta subunit and is a type i membrane protein.