Properties of Ca Currents Activated by T Cell Receptor Signaling
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Influx of extracellular Ca is one of the early biochemical events associated with signaling through the T cell receptor (TCR) complex1–4. The influx of Ca is a critical component of the signaling pathway because it helps to drive the cytoplasmic Ca from resting levels of around 100 nM up to several μM, the concentration required for activation of many intracellular Ca binding proteins and enzymes5. Recently there has been a great deal of progress in understanding the molecular basis of the very earliest events in TCR signaling which precede Ca mobilization as well as those later Ca-dependent processes leading to transcription of the IL-2 gene6–9. Unfortunately, the molecules involved in initiation, maintenance, and termination of Ca influx remain elusive despite the combined efforts of researchers using molecular, biochemical and electrophysiological approaches. However, during the last year a number of important discoveries have generated an unprecedented interest in the nature of the Ca influx pathway10,11.
KeywordsInositol Phosphate Diffusible Messenger Cell Antigen Receptor Signal Transduction
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