Molecular Mechanism of 14-3-3 Protein-mediated Inhibition of Plant Nitrate Reductase

Lambeck, Iris; Fischer-Schrader, Katrin; Niks, Dimitri; Roeper, Juliane; Chi, Jen-Chih; Hille, Russ; Schwarz, Günter

doi:10.1074/jbc.m111.323113

Cited by 59 publications

(65 citation statements)

References 38 publications

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“…Our results rather favor an indirect mechanism by which binding of 14-3-3 dimers causes conformational changes that inhibit SIK catalytic activity. Such structural alterations have been reported for other 14-3-3 ligands including nitrate reductase (NR), RAF proto-oncogene serine/threonine-protein kinase (RAF1), and M-phase inducer phosphatase 2 (CDC25B) [23,40,41]. In case of CDC25B, repression of phosphatase activity is thought to be dependent upon 14-3-3 dimers that form an intramolecular bridge between weak 14-3-3 sites inside the N terminus (S151 or S230) together with the dominant S323 site, blocking cyclin/CDK substrate access as well as impairing access to the nucleus [23,42].…”

Section: Discussionmentioning

confidence: 76%

14‐3‐3 proteins mediate inhibitory effects of cAMP on salt‐inducible kinases (SIKs)

2018

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The salt‐inducible kinase (SIK) family regulates cellular gene expression via the phosphorylation of cAMP‐regulated transcriptional coactivators (CRTCs) and class IIA histone deacetylases, which are sequestered in the cytoplasm by phosphorylation‐dependent 14‐3‐3 interactions. SIK activity toward these substrates is inhibited by increases in cAMP signaling, although the underlying mechanism is unclear. Here, we show that the protein kinase A (PKA)‐dependent phosphorylation of SIKs inhibits their catalytic activity by inducing 14‐3‐3 protein binding. SIK1 and SIK3 contain two functional PKA/14‐3‐3 sites, while SIK2 has four. In keeping with the dimeric nature of 14‐3‐3s, the presence of multiple binding sites within target proteins dramatically increases binding affinity. As a result, loss of a single 14‐3‐3‐binding site in SIK1 and SIK3 abolished 14‐3‐3 association and rendered them insensitive to cAMP. In contrast, mutation of three sites in SIK2 was necessary to fully block cAMP regulation. Superimposed on the effects of PKA phosphorylation and 14‐3‐3 association, an evolutionary conserved domain in SIK1 and SIK2 (the so called RK‐rich region; 595–624 in hSIK2) is also required for the inhibition of SIK2 activity. Collectively, these results point to a dual role for 14‐3‐3 proteins in repressing a family of Ser/Thr kinases as well as their substrates.

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Section: Discussionmentioning

confidence: 76%

14‐3‐3 proteins mediate inhibitory effects of cAMP on salt‐inducible kinases (SIKs)

2018

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“…The NR2 protein binds 14-3-3 through its pSer-534 residue and the 14-3-3 binding results in reduction of its enzymatic activity [63]. We also found that the arginine residues (R) in the 14-3-3 binding site of NR2 were replaced by lysine residues (K), the resulting new motif KKxxpSxP may represent a novel 14-3-3 binding motif.…”

Section: 6mentioning

confidence: 76%

A large-scale protein phosphorylation analysis reveals novel phosphorylation motifs and phosphoregulatory networks in Arabidopsis

Wang

Bian

Cheng

et al. 2013

Journal of Proteomics

101

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“…Conversely, because acetylation and ubiquitylation compete for Lys residues, antagonistic roles are possible (Danielsen et al, 2011;Wagner et al, 2011). Examples of multiply modified proteins include nitrate reductase, which is ubiquitylated (this article), phosphorylated (Lambeck et al, 2012), and SUMOylated (Park et al, 2011), and the AHA H + -ATPases that are regulated by phosphorylation and possibly ubiquitylation (Palmgren, 2001; this article). Intriguingly, we mapped a site for Ub addition on AHA2 to a strictly conserved Lys (Lys-300) close to the phosphorylation site (Asp-329) that regulates its activity and its potential interaction with the 14-3-3/GRF proteins GRF2 and GRF4 (Baunsgaard et al, 1998), which are themselves likely ubiquitylation targets.…”

Section: Discussionmentioning

confidence: 99%

Advanced Proteomic Analyses Yield a Deep Catalog of Ubiquitylation Targets in Arabidopsis

et al. 2013

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The posttranslational addition of ubiquitin (Ub) profoundly controls the half-life, interactions, and/or trafficking of numerous intracellular proteins. Using stringent two-step affinity methods to purify Ub-protein conjugates followed by high-sensitivity mass spectrometry, we identified almost 950 ubiquitylation substrates in whole Arabidopsis thaliana seedlings. The list includes key factors regulating a wide range of biological processes, including metabolism, cellular transport, signal transduction, transcription, RNA biology, translation, and proteolysis. The ubiquitylation state of more than half of the targets increased after treating seedlings with the proteasome inhibitor MG132 (carbobenzoxy-Leu-Leu-Leu-al), strongly suggesting that Ub addition commits many to degradation by the 26S proteasome. Ub-attachment sites were resolved for a number of targets, including six of the seven Lys residues on Ub itself with a Lys-48>Lys-63>Lys-11>>>Lys-33/Lys-29/Lys-6 preference. However, little sequence consensus was detected among conjugation sites, indicating that the local environment has little influence on global ubiquitylation. Intriguingly, the level of Lys-11-linked Ub polymers increased substantially upon MG132 treatment, revealing that they might be important signals for proteasomal breakdown. Taken together, this proteomic analysis illustrates the breadth of plant processes affected by ubiquitylation and provides a deep data set of individual targets from which to explore the roles of Ub in various physiological and developmental pathways.

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Molecular Mechanism of 14-3-3 Protein-mediated Inhibition of Plant Nitrate Reductase

Cited by 59 publications

References 38 publications

14‐3‐3 proteins mediate inhibitory effects of cAMP on salt‐inducible kinases (SIKs)

14‐3‐3 proteins mediate inhibitory effects of cAMP on salt‐inducible kinases (SIKs)

A large-scale protein phosphorylation analysis reveals novel phosphorylation motifs and phosphoregulatory networks in Arabidopsis

Advanced Proteomic Analyses Yield a Deep Catalog of Ubiquitylation Targets in Arabidopsis

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