Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
Proc Natl Acad Sci U S A. 2019 Oct 22;116(43):21893-21899. doi: 10.1073/pnas.1913532116. Epub 2019 Oct 9.
Circadian clock circuitry intersects with a plethora of signaling pathways to adequately time physiological processes to occur at the most appropriate time of the day and year. However, our mechanistic understanding of how the clockwork is wired to its output is limited. Here we uncover mechanistic connections between the core clock component GIGANTEA (GI) and hormone signaling through the modulation of key components of the transduction pathways. Specifically, we show how GI modulates gibberellin (GA) signaling through the stabilization of the DELLA proteins, which act as negative components in the signaling of this hormone. GI function within the GA pathway is required to precisely time the permissive gating of GA sensitivity, thereby determining the phase of GA-regulated physiological outputs.
生物钟电路与众多信号通路相交织，以将生理过程适时地安排在一天和一年中的最佳时间发生。然而，我们对时钟机制如何与其输出连接的机制理解有限。在这里，我们通过调节转导途径的关键组成部分，揭示了核心时钟组件 GI 和激素信号之间的机制联系。具体来说，我们展示了 GI 如何通过稳定 DELLA 蛋白来调节赤霉素 (GA) 信号，DELLA 蛋白在该激素信号中充当负成分。GI 在 GA 途径中的功能对于精确控制 GA 敏感性的许可门控是必需的，从而决定了 GA 调节生理输出的相位。
