14‐3‐3 proteins regulate photomorphogenesis by facilitating light‐induced degradation of PIF3

Abstract

14-3-3s are highly conserved phosphopeptide-binding proteins that play important roles in various developmental and signaling pathways in plants. However, although protein phosphorylation has been proven to be a key mechanism for regulating many pivotal components of the light signaling pathway, the role of 14-3-3 proteins in photomorphogenesis remains largely obscure. PHYTOCHROME-INTERACTING FACTOR3 (PIF3) is an extensively studied transcription factor repressing photomorphogenesis, and it is well-established that upon red (R) light exposure, photo-activated phytochrome B (phyB) interacts with PIF3 and induces its rapid phosphorylation and degradation. PHOTOREGULATORY PROTEIN KINASES (PPKs), a family of nuclear protein kinases, interact with phyB and PIF3 in R light and mediate multisite phosphorylation of PIF3 in vivo.Here, we report that two members of the 14-3-3 protein family, 14-3-3k and j, bind to a serine residue in the bHLH domain of PIF3 that can be phosphorylated by PPKs, and act as key positive regulators of R light-induced photomorphogenesis.Moreover, 14-3-3k and j preferentially interact with photo-activated phyB and promote the phyB-PIF3-PPK complex formation, thereby facilitating phyB-induced phosphorylation and degradation of PIF3 upon R light exposure.Together, our data demonstrate that 14-3-3k and j work in close concert with the phyB-PIF3 module to regulate light signaling in Arabidopsis.

A 14-3-3 Protein-Encoding Gene, BdGF14g, Confers Better Drought Tolerance by Regulating ABA Biosynthesis and Signaling

“…In addition, an increasing number of 14-3-3 proteins have been found to play cardinal roles in plants that cope with adverse abiotic stresses. In the present study, a 14-3-3 protein, BdGF14g, was extracted from B. distachyon located in the whole tobacco cell (Figure 1), and it was similar not only to the reported 14-3-3 proteins in B. distachyon, BdGF14d and BdGF14b [24,43], but also to 14-3-3 proteins in other plants such as At14-3-3λ and OsGF14f [14,25,44]. The cytoplasm nucleus localization of 14-3-3λ-GFP had no obvious change under different light conditions [14], but significantly strong GFP signals were observed in the nuclei of root cells after 4 • C treatment [44].…”

“…Similarly, under LP conditions, OsGF14b responds to qPE9-1, exhibiting a higher phosphorus uptake by modulating root elongation [11]. Moreover, 14-3-3 proteins such as florigen Hd3a, NPH3, and phyB-PIF3 receptors are involved in light signal transmission [12][13][14]. Under long-day conditions, these proteins form a ternary florigen activation complex (FAC) with OsFD1 and RFT1 to promote flowering [15].…”

Tuning the Wavelength: Manipulation of Light Signaling to Control Plant Defense

“…The 14-3-3 proteins may have many pleiotropic functions but also interact with NRL proteins to modulate their activity following BL perception [ 98 ]. However, 14-3-3 proteins have been recently demonstrated to promote the degradation of PIF3 through interactions with activated phyB and MLKs [ 100 ], showing that RL and BL share certain signaling components.…”

Photodegradable by Yellow-Orange Light degFusionRed Optogenetic Module with Autocatalytically Formed Chromophore

“…Green light activates bacterial transcription factor CarH (~525 nm), requiring cyanocobalamin (vitamin B12) [ 16 ] and the dissociation of PCB-dependent cyanobacteriochrome Am1_c0023g2 (~525 nm) and its partner BAm green [ 17 ]. Far-red (650–750) light activates the binding of PCB-dependent phytochrome B (PhyB) to PIF3 [ 18 ] or PIF6 [ 19 ]; biliverdin-dependent photosensors include c-di-GMP-producing BphS (~730 nm) [ 20 ], MagRed pair [ 21 ] (~660 nm) and oligomerizing iLight [ 22 ] (~660 nm). Near-infrared (NIR) light (750–900 nm) activates biliverdin-dependent bacteriophytochrome-based Rp BphP1-PpsR2 [ 23 ] and Rp BphP1-QPAS1 [ 2 ] (~780 nm) pairs.…”