Transient receptor potential melastatin-3 (TRPM3)-induced activation of AP-1 requires Ca2+ ions and the transcription factors c-Jun, ATF2, and ternary complex factor.

The steroid pregnenolone sulfate activates the transcription factor activator protein-1 (AP-1) via stimulation of transient receptor potential melastatin-3 (TRPM3) channels. Here, we show that the signaling pathway requires an influx of Ca(2+) ions into the cells and a rise in the intracellular Ca(2+) levels. The upregulation of AP-1 was attenuated in cells that overexpressed mitogen activated protein kinase phosphatase-1, indicating that Ca(2+) ions prolong the signaling cascade via activation of mitogen activated protein kinases.