Volume 8, Number 4, p.p. 111–114
Glutamate downregulates the NR2A subunit of the NMDA-glutamate receptor and decreases the production of cAMP in Jurkat lymphoid T cells
S. Koriauli, N. Natsvlishvili and D. Mikeladze
Department of Biochemistry, I. Beritashvili Institute of Physiology, 14 Gotua St, 0160 Tbilisi, Georgia
Human T lymphocytes expose both ionotropic and metabotropic glutamate receptors, which control the immune responses, cell activation, maturation, and death. We have examined the effect of glutamate on the content of the NMDA-glutamate receptor (NMDA-R) subunits and the production of cyclic AMP (cAMP) in human leukaemia Jurkat cells. Western blots applied to the NR2A and NR2B subunits of the NMDA-glutamate receptor revealed that a long-term (48 h) treatment of Jurkat cells by glutamate, at concentrations within normal plasma levels (10–5 M), in contrast to low concentration (3 × 10–7 M), downregulates the NR2A subunit, probably by internalization. Furthermore, we found that Jurkat cells with noninternalized NR2A secreted more cAMP than lymphocytes with downregulated NR2A. These findings indicate that the activity of the NMDA-glutamate receptor depends on the levels of cAMP in the cells and suggests that lymphocytes expose the active NMDA-glutamate receptor only in low glutamate milieux.
Keywords:
cAMP, NMDA-glutamate receptor, T-lymphocyte