Arabidopsis COP1/SPA1 complex and FHY1/FHY3 associate with distinct phosphorylated forms of phytochrome A in balancing light signaling.

ABSTRACT: Fine tuning of light signaling is crucial to plant development. Following light-triggered nuclear translocation, the photoreceptor phytochrome A (phyA) regulates gene expression under continuous far-red light and is rapidly destabilized upon red light irradiation by E3 ubiquitin ligases, including COP1. Here we provide evidence that the light signaling repressors SPA proteins contribute to COP1-mediated phyA degradation and that a COP1/SPA1 protein complex is tightly associated with phyA ubiquitination activity. Furthermore, a phosphorylated phyA form accumulates in the nucleus and preferentially associates with the COP1/SPA1 complex. In contrast, underphosphorylated phyA predominantly associates with the phyA-signaling intermediates FHY3 and FHY1. However, COP1 associates with underphosph

SUBMITTER: Saijo Y 

PROVIDER: S-EPMC2597559 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature