scholarly journals NRT2.1 phosphorylation prevents root high affinity nitrate uptake activity in Arabidopsis thaliana

2019 ◽  
Author(s):  
Aurore Jacquot ◽  
Valentin Chaput ◽  
Adeline Mauries ◽  
Zhi Li ◽  
Pascal Tillard ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transgenic Plants ◽  
Translational Regulation ◽  
Nitrate Uptake ◽  
Phosphorylation Site ◽  
Relative Level ◽  
High Affinity ◽  
Proteomic Approach ◽  
C Terminus ◽  
Main Component

AbstractIn Arabidopsis thaliana, NRT2.1 codes for a main component of the root nitrate high-affinity transport system. Previous studies revealed that post-translational regulation of NRT2.1 plays an important role in the control of root nitrate uptake and that one mechanism could correspond to NRT2.1 C-terminus processing. To further investigate this hypothesis, we produced transgenic plants with truncated forms of NRT2.1. It revealed an essential sequence for NRT2.1 activity, located between the residues 494-513. Using a phospho-proteomic approach, we found that this sequence contains one phosphorylation site, at serine 501, which can inactivate NRT2.1 function when mimicking the constitutive phosphorylation of this residue in transgenic plants. This phenotype could neither be explained by changes in abundance of NRT2.1 and NAR2.1, a partner protein of NRT2.1, nor by a lack of interaction between these two proteins. Finally, the relative level of serine 501 phosphorylation was found to be modulated by nitrate in wildtype plants. Altogether, these observations allowed us to propose a model for a new and essential mechanism for the regulation of NRT2.1 activity.

NRT2.1 C‐terminus phosphorylation prevents root high affinity nitrate uptake activity in Arabidopsis thaliana

2020 ◽  
Vol 228 (3) ◽  
pp. 1038-1054 ◽  
Author(s):  
Aurore Jacquot ◽  
Valentin Chaput ◽  
Adeline Mauries ◽  
Zhi Li ◽  
Pascal Tillard ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Nitrate Uptake ◽  
High Affinity ◽  
C Terminus ◽  
Uptake Activity

Spastin Interacts with CRMP2 to Regulate Neurite Outgrowth by Controlling Microtubule Dynamics through Phosphorylation Modifications

2020 ◽  
Vol 19 ◽  
Author(s):  
Sumei Li ◽  
Jifeng Zhang ◽  
Jiaqi Zhang ◽  
Jiong Li ◽  
Longfei Cheng ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Hippocampal Neurons ◽  
Neuronal Development ◽  
Phosphorylation Site ◽  
Microtubule Dynamics ◽  
Microtubule Assembly ◽  
C Terminus ◽  
Mediator Protein ◽  
Branch Formation

Aims: Our work aims to revealing the underlying microtubule mechanism of neurites outgrowth during neuronal development, and also proposes a feasible intervention pathway for reconstructing neural network connections after nerve injury. Background: Microtubule polymerization and severing are the basis for the neurite outgrowth and branch formation. Collapsin response mediator protein 2 (CRMP2) regulates axonal growth and branching as a binding partner of the tubulin heterodimer to promote microtubule assembly. And spastin participates in the growth and regeneration of neurites by severing microtubules into small segments. However, how CRMP2 and spastin cooperate to regulate neurite outgrowth by controlling the microtubule dynamics needs to be elucidated. Objective: To explore whether neurite outgrowth was mediated by coordination of CRMP2 and spastin. Method: Hippocampal neurons were cultured in vitro in 24-well culture plates for 4 days before being used to perform the transfection. Calcium phosphate was used to transfect the CRMP2 and spastin constructs and their control into the neurons. An interaction between CRMP2 and spastin was examined by using pull down, CoIP and immunofluorescence colocalization assays. And immunostaining was also performed to determine the morphology of neurites. Result: We first demonstrated that CRMP2 interacted with spastin to promote the neurite outgrowth and branch formation. Furthermore, our results identified that phosphorylation modification failed to alter the binding affinities of CRMP2 for spastin, but inhibited their binding to microtubules. CRMP2 interacted with the MTBD domain of spastin via its C-terminus, and blocking the binding sites of them inhibited the outgrowth and branch formation of neurites. In addition, we confirmed one phosphorylation site S210 at spastin in hippocampal neurons and phosphorylation spastin at site S210 promoted the neurite outgrowth but not branch formation by remodeling microtubules. Conclusion: Taken together, our data demonstrated that the interaction of CRMP2 and spastin is required for neurite outgrowth and branch formation and their interaction is not regulated by their phosphorylation.

scholarly journals Mechanical force effect on the two-state equilibrium of the hyaluronan-binding domain of CD44 in cell rolling

2015 ◽  
Vol 112 (22) ◽  
pp. 6991-6996 ◽  
Author(s):  
Takashi Suzuki ◽  
Miho Suzuki ◽  
Shinji Ogino ◽  
Ryo Umemoto ◽  
Noritaka Nishida ◽  
...  
Keyword(s):  
Shear Stress ◽  
Conformational Change ◽  
Mechanical Force ◽  
Binding Domain ◽  
Terminal Region ◽  
Hematopoietic Progenitor Cell ◽  
High Shear ◽  
Cell Rolling ◽  
High Affinity ◽  
C Terminus

CD44 is the receptor for hyaluronan (HA) and mediates cell rolling under fluid shear stress. The HA-binding domain (HABD) of CD44 interconverts between a low-affinity, ordered (O) state and a high-affinity, partially disordered (PD) state, by the conformational change of the C-terminal region, which is connected to the plasma membrane. To examine the role of tensile force on CD44-mediated rolling, we used a cell-free rolling system, in which recombinant HABDs were attached to beads through a C-terminal or N-terminal tag. We found that the rolling behavior was stabilized only at high shear stress, when the HABD was attached through the C-terminal tag. In contrast, no difference was observed for the beads coated with HABD mutants that constitutively adopt either the O state or the PD state. Steered molecular dynamics simulations suggested that the force from the C terminus disrupts the interaction between the C-terminal region and the core of the domain, thus providing structural insights into how the mechanical force triggers the allosteric O-to-PD transition. Based on these results, we propose that the force applied from the C terminus enhances the HABD–HA interactions by inducing the conformational change to the high-affinity PD transition more rapidly, thereby enabling CD44 to mediate lymphocyte trafficking and hematopoietic progenitor cell homing under high-shear conditions.

scholarly journals Comparison of two Turnip mosaic virus P1 proteins in their ability to co-localize with the Arabidopsis thaliana G3BP-2 protein

Virus Genes ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 233-237
Author(s):  
Hendrik Reuper ◽  
Björn Krenz
Keyword(s):  
Arabidopsis Thaliana ◽  
Mosaic Virus ◽  
Specific Interaction ◽  
Viral Proteins ◽  
Turnip Mosaic Virus ◽  
Stress Conditions ◽  
C Terminus ◽  
Positive Sense ◽  
Key Factor ◽  
Large Host

AbstractTurnip mosaic virus (TuMV), belonging to the genus Potyvirus (family Potyviridae), has a large host range and consists of a single-stranded positive sense RNA genome encoding 12 proteins, including the P1 protease. This protein which is separated from the polyprotein by cis cleavage at its respective C-terminus, has been attributed with different functions during potyviral infection of plants. P1 of Turnip mosaic virus (P1-TuMV) harbors an FGSF-motif and FGSL-motif at its N-terminus. This motif is predicted to be a binding site for the host Ras GTPase-activating protein-binding protein (G3BP), which is a key factor for stress granule (SG) formation in mammalian systems and often targeted by viruses to inhibit SG formation. We therefore hypothesized that P1-TuMV might interact with G3BP to control and regulate plant SGs to optimize cellular conditions for the production of viral proteins. Here, we analyzed the co-localization of the Arabidopsis thaliana G3BP-2 with the P1 of two TuMV isolates, namely UK 1 and DEU 2. Surprisingly, P1-TuMV-DEU 2 co-localized with AtG3BP-2 under abiotic stress conditions, whereas P1-TuMV-UK 1 did not. AtG3BP-2::RFP showed strong SGs formation after stress, while P1-UK 1::eGFP maintained a chloroplastic signal under stress conditions, the signal of P1-DEU 2::eGFP co-localized with that of AtG3BP-2::RFP. This indicates a specific interaction between P1-DEU 2 and the AtG3BP family which is not solely based on the canonical interaction motifs.

scholarly journals PhosPhAt: a database of phosphorylation sites in Arabidopsis thaliana and a plant-specific phosphorylation site predictor

2007 ◽  
Vol 36 (Database) ◽  
pp. D1015-D1021 ◽  
Author(s):  
J. L. Heazlewood ◽  
P. Durek ◽  
J. Hummel ◽  
J. Selbig ◽  
W. Weckwerth ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Phosphorylation Site ◽  
Phosphorylation Sites

The shoot is important for high-affinity nitrate uptake in Egeria densa, a submerged vascular plant

2012 ◽  
Vol 125 (5) ◽  
pp. 669-678 ◽  
Author(s):  
Shu Takayanagi ◽  
Yuma Takagi ◽  
Akifumi Shimizu ◽  
Hiroshi Hasegawa
Keyword(s):  
Nitrate Uptake ◽  
Vascular Plant ◽  
Egeria Densa ◽  
High Affinity

scholarly journals Dehiscence-related expression of an Arabidopsis thaliana gene encoding a polygalacturonase in transgenic plants of Brassica napus

1999 ◽  
Vol 22 (2) ◽  
pp. 159-167 ◽  
Author(s):  
E. S. JENKINS ◽  
W. PAUL ◽  
M. CRAZE ◽  
C. A. WHITELAW ◽  
A. WEIGAND ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Brassica Napus ◽  
Transgenic Plants ◽  
Gene Encoding

IRON MAN interacts with BRUTUS to maintain iron homeostasis in Arabidopsis

2021 ◽  
Vol 118 (39) ◽  
pp. e2109063118
Author(s):  
Yang Li ◽  
Cheng Kai Lu ◽  
Chen Yang Li ◽  
Ri Hua Lei ◽  
Meng Na Pu ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Iron Homeostasis ◽  
Fe Deficiency ◽  
Small Peptides ◽  
Interaction Domain ◽  
C Terminus ◽  
Positive Regulators ◽  
Fe Homeostasis ◽  
And Function

IRON MAN (IMA) peptides, a family of small peptides, control iron (Fe) transport in plants, but their roles in Fe signaling remain unclear. BRUTUS (BTS) is a potential Fe sensor that negatively regulates Fe homeostasis by promoting the ubiquitin-mediated degradation of bHLH105 and bHLH115, two positive regulators of the Fe deficiency response. Here, we show that IMA peptides interact with BTS. The C-terminal parts of IMA peptides contain a conserved BTS interaction domain (BID) that is responsible for their interaction with the C terminus of BTS. Arabidopsis thaliana plants constitutively expressing IMA genes phenocopy the bts-2 mutant. Moreover, IMA peptides are ubiquitinated and degraded by BTS. bHLH105 and bHLH115 also share a BID, which accounts for their interaction with BTS. IMA peptides compete with bHLH105/bHLH115 for interaction with BTS, thereby inhibiting the degradation of these transcription factors by BTS. Genetic analyses suggest that bHLH105/bHLH115 and IMA3 have additive roles and function downstream of BTS. Moreover, the transcription of both BTS and IMA3 is activated directly by bHLH105 and bHLH115 under Fe-deficient conditions. Our findings provide a conceptual framework for understanding the regulation of Fe homeostasis: IMA peptides protect bHLH105/bHLH115 from degradation by sequestering BTS, thereby activating the Fe deficiency response.

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