G alpha16 protein expression is up- and down-regulated following T-cell activation: disruption of this regulation impairs activation-induced cell responses
Lippert, E.; Baltensperger, K.; Jacques, Y.; Hermouet, S.
Febs Letters 417(3): 292-296
1997
ISSN/ISBN: 0014-5793 PMID: 9409736 DOI: 10.1016/s0014-5793(97)01308-2
Accession: 046141625
The role of heterotrimeric G proteins in T-cell activation is poorly understood. Here we show that in normal, mature human T-cells, expression of G alpha16, the 43 kDa alpha subunit of G16, varies widely, depending on T-cell activation status. Quiescent blood lymphocytes strongly up-regulate G alpha16 after Leuco A stimulation: protein expression of G alpha16 is maximal at day 4, then decreases. Consistently, in human T-cell clones, expression of G alpha16 is high in the first week following activation and decreases rapidly within the second week. In addition, permanent disruption of regulated G alpha16 expression in Jurkat T-cells by stable overexpression of 43 kDa G alpha16 inhibited Leuco A-induced interleukin-2 production, CD69 up-regulation and cell apoptosis (by 58%, 46% and 74%, respectively), suggesting that coordinate regulation of G alpha16 expression is necessary for optimal activation-induced T-cell responses, and that G alpha16 proteins may be involved in the negative regulation of TCR signalling.