NA in human T cells results in loss of anti-CD3/CD28-mediated Th2 cytokine expression [12].
In order for GATA-3 to regulate gene expression, it must translocate from the cytoplasm into the nucleus to access its target genes. Enhanced nuclear expression of GATA-3 following T cell receptor activation was first demonstrated in murine T cells [13] and was recently confirmed in human T cells following T cell receptor and co-receptor stimulation [12]. GATA-3 contains a classical nuclear import signal [14] and is transported into the nucleus by the nuclear import protein importin-α (also known as karyopherin-α) [12]. Deletion of a region encompassing the GATA-3 nuclear localisation sequence (NLS) region in murine and human cells prevents its nuclear localisation [12],[14]. The affinity of the importin-α–NLS interaction is regulated by phos