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

In 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.

Patterned cortical tension mediated by N-cadherin controls cell geometric order in the eye.

Adhesion molecules hold cells together but also couple cell membranes to a contractile actomyosin network, which limits the expansion of cell contacts. Despite their fundamental role in tissue morphogenesis and tissue homeostasis, how adhesion molecules control cell shapes and cell patterns in tissues remains unclear. Here we address this question in vivo using the eye.

Evidence for participation of the methionine sulfoxide reductase repair system in plant seed longevity.

Seeds are in a natural oxidative context leading to protein oxidation. Although inevitable for proper progression from maturation to germination, protein oxidation at high levels is detrimental and associated with seed aging. Oxidation of methionine to methionine sulfoxide is a common form of damage observed during aging in all organisms.

Involvement of thioredoxin y2 in the preservation of leaf methionine sulfoxide reductase capacity and growth under high light.

Methionine (Met) in proteins can be oxidized to two diastereoisomers of methionine sulfoxide, Met-S-O and Met-R-O, which are reduced back to Met by two types of methionine sulfoxide reductases (MSRs), A and B, respectively. MSRs are generally supplied with reducing power by thioredoxins. Plants are characterized by a large number of thioredoxin isoforms, but those providing electrons to MSRs in vivo are not known.

Regulation of high-affinity nitrate uptake in roots of Arabidopsis depends predominantly on posttranscriptional control of the NRT2.1/NAR2.1 transport system.

In Arabidopsis (Arabidopsis thaliana), the NRT2.1 gene codes for the main component of the root nitrate (NO(3)(-)) high-affinity transport system (HATS). Due to the strong correlation generally found between high-affinity root NO(3)(-) influx and NRT2.

Nitrate transceptor(s) in plants.

The availability of mineral nutrients in the soil dramatically fluctuates in both time and space. In order to optimize their nutrition, plants need efficient sensing systems that rapidly signal the local external concentrations of the individual nutrients. Until recently, the most upstream actors of the nutrient signalling pathways, i.

Plant thioredoxin CDSP32 regenerates 1-cys methionine sulfoxide reductase B activity through the direct reduction of sulfenic acid.

Thioredoxins (Trxs) are ubiquitous enzymes catalyzing the reduction of disulfide bonds, thanks to a CXXC active site. Among their substrates, 2-Cys methionine sulfoxide reductases B (2-Cys MSRBs) reduce the R diastereoisomer of methionine sulfoxide (MetSO) and possess two redox-active Cys as follows: a catalytic Cys reducing MetSO and a resolving one, involved in disulfide bridge formation. The other MSRB type, 1-Cys MSRBs, possesses only the catalytic Cys, and their regeneration mechanisms by Trxs remain unclear.

Arabidopsis thaliana plastidial methionine sulfoxide reductases B, MSRBs, account for most leaf peptide MSR activity and are essential for growth under environmental constraints through a role in the preservation of photosystem antennae.

Methionine oxidation to methionine sulfoxide (MetSO) is reversed by two types of methionine sulfoxide reductases (MSRs), A and B, specific to MetSO S- and R-diastereomers, respectively. Two MSRB isoforms, MSRB1 and MSRB2, are present in chloroplasts of Arabidopsis thaliana. To assess their physiological role, we characterized Arabidopsis mutants knockout for the expression of MSRB1, MSRB2 or both genes.

Protein-repairing methionine sulfoxide reductases in photosynthetic organisms: gene organization, reduction mechanisms, and physiological roles.

Methionine oxidation to methionine sulfoxide (MetSO) is reversed by two types of methionine sulfoxide reductases (MSRs), A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found in most organisms from bacteria to human. In the current review, we first compare the organization of the MSR gene families in photosynthetic organisms from cyanobacteria to higher plants.

Regeneration mechanisms of Arabidopsis thaliana methionine sulfoxide reductases B by glutaredoxins and thioredoxins.

Methionine oxidation leads to the formation of S- and R-diastereomers of methionine sulfoxide (MetSO), which are reduced back to methionine by methionine sulfoxide reductases (MSRs) A and B, respectively. MSRBs are classified in two groups depending on the conservation of one or two redox-active Cys; 2-Cys MSRBs possess a catalytic Cys-reducing MetSO and a resolving Cys, allowing regeneration by thioredoxins. The second type, 1-Cys MSRBs, possess only the catalytic Cys.

Specificity of thioredoxins and glutaredoxins as electron donors to two distinct classes of Arabidopsis plastidial methionine sulfoxide reductases B.

Methionine sulfoxide reductases (MSRs) A and B reduce methionine sulfoxide (MetSO) S- and R-diastereomers, respectively, back to Met using electrons generally supplied by thioredoxin. The physiological reductants for MSRBs remain unknown in plants, which display a remarkable variety of thioredoxins (Trxs) and glutaredoxins (Grxs). Using recombinant proteins, we show that Arabidopsis plastidial MSRB1 and MSRB2, which differ regarding the number of presumed redox-active cysteines, possess specific reductants.

Studies on the reducing systems for plant and animal thioredoxin-independent methionine sulfoxide reductases B.

Two distinct stereospecific methionine sulfoxide reductases (Msr), MsrA and MsrB reduce the oxidized methionine (Met), methionine sulfoxide [Met(O)], back to Met. In this report, we examined the reducing systems required for the activities of two chloroplastic MsrB enzymes (NtMsrB1 and NtMsrB2) from tobacco (Nicotiana tabacum). We found that NtMrsB1, but not NtMsrB2, could use dithiothreitol as an efficient hydrogen donor.

A critical role of teashirt for patterning the ventral epidermis is masked by ectopic expression of tiptop, a paralog of teashirt in Drosophila.

The teashirt gene encodes a protein with three widely spaced zinc finger motifs that is crucial for specifying trunk identity in Drosophila embryos. Here, we describe a gene called tiptop, which encodes a protein highly similar to Teashirt. We have analyzed the expression patterns and functions of these two genes in the trunk of the embryo.