IP3 RECEPTOR - LOCALIZATION TO PLASMA-MEMBRANE OF T-CELLS AND COCAPPING WITH THE T-CELL RECEPTOR

Immune responses in lymphocytes require cellular accumulation of large amounts of calcium (Ca2+) from extracellular sources. In the T cell tumor line Jurkat, receptors for the Ca2+-releasing messenger inositol 1,4,5-trisphosphate (IP3) were localized to the plasma membrane (PM). Capping of the T cell receptor-CD3 complex, which is associated with signal transduction, was accompanied by capping of IP3 receptors. The IP3 receptor on T cells appears to be responsible for the entry of Ca2+ that initiates proliferative responses.