Negative regulatory role of Annexin-A1 in 14-3-3η-mediated glucocorticoid receptor transcriptional activation

Annexin-A1 (ANX-1) is involved in glucocorticoid receptor (GR)-mediated signal transduction. However, the molecular mechanism by which ANX-1 plays a role in GR signaling is not fully understood. Recently, we reported that 14-3-3η inhibits degradation of GR, resulting in an increase in GR transcriptional activity. In this study, we have addressed the role of ANX-1 in 14-3-3η-induced enhancement of GR transactivation. ANX-1 abolished the increase in GR transcriptional activity due to 14-3-3η. ANX-1 had no effect on the protein level of GR. However, ANX-1 abrogated the inhibitory effect of 14-3-3η on GR degradation, which causes a decrease in GR stability in the nucleus. Our results indicate that ANX-1 functions as a negative regulator of GR transcriptional activation by inhibiting 14-3-3η-induced up-regulation of GR.