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To understand stress response mechanisms, a multiple stress-responsive gene OsPM1 with a disordered region containing about 30 amino acid residues was screened by microarray. Promoter region analysis using PlantCARE showed this gene contains multiple cis-regulatory elements responding to abiotic stresses. Quantitative real-time PCR and promoter-GUS transgenic plant analysis verified that OsPM1 was induced by multiple abiotic stresses. OsPM1-GFP fusion protein expression showed that OsPM1 was localized at the cell membrane. The rice plants overexpressing OsPM1 exhibited hypersensitivity to salt stress but enhanced drought tolerance compared to the wild-type plants; the rice plants expressing antisense of OsPM1 were hyposensitive to salt stress but with weak drought tolerance compared to the wild-type plants. These results showed OsPM1 is a positive regulator of rice tolerance to drought, but it’s also a negative regulator of rice tolerance to salt.

The negative regulator of G-protein signalling 4 (Rgs4) is linked to several neurologic diseases, e.g. schizophrenia, addiction, seizure and pain perception. Consequently, Rgs4 expression is tightly regulated, resulting in high mRNA and protein turnover. The post-transcriptional control of gene expression is mediated via RNA-binding proteins (RBPs) that interact with mRNAs in a combinatorial fashion. Here, we show that in neurons the RBP HuR reduces endogenous Rgs4 expression by destabilizing Rgs4 mRNA. Interestingly, in smooth muscle cells, Rgs4 is stabilized by HuR, indicating tissue-dependent differences in HuR function. Using in vitro RNA-based pulldown experiments, we identify the functional AU-rich element (ARE) within the Rgs4 3ʹ-UTR that is recognized and bound by HuR. Bioinformatic analysis uncovered that this ARE lies within a highly conserved area next to a miR-26 binding site. We find that the neuronal-enriched miR-26 negatively influences Rgs4 expression in neurons. Further, HuR and miR-26 act synergistically in fluorescent reporter assays. Together, our data suggest a regulatory mechanism, in which an RBP selectively destabilizes a target mRNA in cooperation with a miRNA and the RISC machinery.

Myostatin (MSTN) gene, also known as growth and differentiation factor 8 (GDF8) gene, is a negative regulator of skeletal muscle growth and development, especially the number, size and type of musc...

MicroRNAs (miRNAs) are small regulatory RNAs of relatively long half-life in non-proliferative human cells. However, in cancer cells the half-lives of miRNAs are comparatively short. To understand the mechanism of rapid miRNA turnover in cancer cells, we explored the effect of target mRNAs on the abundance of the miRNAs that repress them. We have noted an accelerated extracellular vesicle (EV)-mediated export of miRNAs in presence of their target mRNAs in mammalian cells, and this target-driven miRNA-export process is retarded by Ago2-interacting protein GW182B. The GW182 group of proteins are localized to GW182 bodies or RNA processing bodies in mammalian cells, and GW182B-dependent retardation of miRNA export depends on GW body integrity and is independent of the HuR protein-mediated auxiliary pathway of miRNA export. Our data thus support the existence of a HuR-independent pathway of miRNA export in human cells that can be targeted in MDA-MB-231 cancer cells, to increase the level of cellular let-7a, a known negative regulator of cancer growth.

Target of rapamycin complex 1 (TORC1) promotes cellular anabolism and suppresses macroautophagy/autophagy. In mammalian cells starved of amino acid, the GATOR1 complex, a negative regulator of TORC1, is released from its inhibitor GATOR2 and inactivates TORC1. We have recently identified the evolutionarily conserved GATOR2 components in fission yeast including Sea3, an ortholog of mammalian WDR59, but, unexpectedly, Sea3 acts as a part of GATOR1 to suppress TORC1. Moreover, fission yeast GATOR1 is not required for the amino-acid starvation-induced TORC1 attenuation, which is instead mediated by the Gcn2 pathway. Conversely, absence of a nitrogen source suppresses TORC1 in a manner dependent on GATOR1 as well as the Tsc1-Tsc2 complex, whose mammalian equivalent functions as a growth-factor sensitive TORC1 inhibitor. Thus, the evolutionarily conserved signaling modules are utilized differently between fission yeast and mammals to control TORC1 activity and autophagy.

The cation-dependent galactose-specific flocculation activity of the Schizosaccharomyces pombe null mutant of lkh1+, the gene encoding LAMMER kinase homolog, has previously been reported by our group. Here, we show that disruption of prk1+, another flocculation associated regulatory kinase encoding gene, also resulted in cation-dependent galactose-specific flocculation. Deletion of prk1 increased the flocculation phenotype of the lkh1+ null mutant and its overexpression reversed the flocculation of cells caused by lkh1 deletion. Transcript levels of prk1+ were also decreased by lkh1+ deletion. Cumulatively, these results indicate that Lkh1 is one of the negative regulators acting upstream of Prk1, regulating non-sexual flocculation in fission yeast.

The programmed death-1 receptor, PD-1, is a negative regulator of T-cell activation. The PD-1.3 polymorphism of the PD-1 gene (PDCD1) has been previously shown to be associated with several autoimmune and inflammatory disorders including systemic lupus erythematosus and multiple sclerosis. We examined for the first time PD-1.3 association with another inflammatory disease with strong immune component, IgE-mediated bronchial asthma, its severity and its biochemical markers (total serum IgE and IL-4).PD-1.3 G/A was genotyped by PCR-RFLP analysis using two different populations: Caucasian (492 Russian individuals) and Asian (276 Buryat individuals).We found a significant association of the PD-1.3 polymorphism with IgE-mediated bronchial asthma and total serum IgE level in the Russian population. Combined genotype AA+AG was correlated with risk of developing allergic bronchial asthma (OR = 1.78, 95% CI 1.13-2.78, p = 0.011) and lower concentrations of total serum IgE (p = 0.001) compared with the wild-type genotype GG. However, PD-1.3 was not polymorphic in the Buryat population.PD-1.3 polymorphism of the PD-1 gene (PDCD1) may contribute to the development of allergic asthma in the Russians but not in the Buryats. Our results could be helpful for a better understanding of the effect of this polymorphism on the development of diseases with strong immune components.

The mechanism underlying the increased rate of endogenous glucose production from the liver during exercise remains unknown. The cytokine interleukin-6 (IL-6) is known to be released during exercise and is thought that either IL-6 directly or via a "contraction factor" stimulates the release of stored glucose from the liver. Here we show that IL-6 does not directly increase hepatic glucose output (HGO). Moreover, IL-6 infused at the same time as glucagon caused a significant reduction in HGO. IL-6 infused with epinephrine caused no synergenic increase in HGO. To test if an unknown "contraction factor" was needed along with IL-6 to increase HGO, we used human fasted and exercised plasma perfused with or without IL-6 in our isolated liver system. We found that exercised plasma increased HGO, as expected, but when infused with IL-6, reductions in HGO were found. Our results provide evidence that IL-6 works as a negative regulator of HGO.

Response to targeted therapies is limited by the activation or inhibition of feedback loops. Here we report the ubiquitin specific peptidase 28/F-box WD repeat-containing protein 7 (USP28/FBW7) complex functions as a negative regulator of mitogen-activated protein kinase (MAPK) pathway by targeting v-raf murine sarcoma viral oncogene homolog B (BRAF) for degradation, a process which is lost in a large proportion of BRAF mutant melanoma patients, resulting in resistance to BRAF inhibitor therapies.

The objective of this study was to examine the effect of maternal immunisation against myostatin, a potent negative regulator of skeletal muscle growth, on the skeletal muscle growth of offspring in mice. Twenty female mice were divided into four groups and immunised against keyhole limpet haemocyanin (control) or recombinant mature myostatin (rMyo), or two different myostatin synthetic peptides conjugated to keyhole limpet haemocyanin (Myo1 and Myo2). Offspring were sacrificed at 8 weeks of age to measure carcass, muscle and fat masses. Sera collected from 3-day-old neonates of the rMyo, Myo1 and Myo2 groups showed titres against myostatin, confirming the maternal transfer of anti-myostatin antibodies to offspring. No significant effects of immunisation on offspring weight were observed. The offspring of the Myo2 group, but not the rMyo and Myo1 groups, had significantly heavier gastrocnemius and triceps muscle mass than those of the control (p

Objective. Inflammatory bowel diseases (IBD) have a complex genetic background. The interleukin receptor associated kinase-M (IRAK-M) is a NF-kappa B-mediated, negative regulator of Toll-like receptor (TLR) signaling. A functional mutation in a negative regulator might induce impaired endotoxin tolerance and increased inflammatory responses. IRAK-M is situated on chromosome 12q14, a susceptibility locus for IBD, which makes it a good candidate gene. The objective of the study was to analyze a large cohort of IBD patients for the association between IBD and IRAK-M. Material and methods. A total of 542 patients with IBD (309 Crohn's disease (CD), 233 ulcerative colitis (UC)) and 305 controls were studied. Two single nucleotide polymorphisms (V147I and V270I) and six microsatellite markers were evaluated using association analysis and the haplotype sharing statistic. Results were stratified for CARD15 mutations R702W, G908R and 1007fsinsC. Results. No significant differences in IRAK-M allele frequencies were observed between IBD, UC, CD or subgroups of CD or UC and controls. Five out of 36 UC patients (13.9%) with an IBD-associated CARD15 mutation were carriers versus 2/ 167 (1.2%) in non-carriers (OR 13.1, 95% CI 1.0 -164.5). No interaction was observed for CD. Conclusions. No evidence was found to suggest an association between IBD, CD, UC or subsets of CD and UC and IRAK-M. However, an interaction was found between IRAK-M and CARD15 in UC patients. In CARD15 mutant patients, the production of IRAK-M upon stimulation might be impaired. Further studies are needed to determine whether an impaired negative regulation of the TLR-signaling pathway might be partly responsible for the development of IBD.

AtGRP3 is a glycine-rich protein from Arabidopsis thaliana shown to interact with the extracellular domain of the receptor-like kinase (RLK) AtWAK1. Based on previous functional data for AtWAK1, a model was proposed that AtGRP3 when bound to this RLK would negatively regulate its kinase activity, inhibiting cell expansion. Here, we review recent functional studies on AtGRP3 that corroborate this model and suggest that AtGRP3/AtWAK1 complex regulates also defense signaling pathways. On the other hand, we show new data on AtGRP3-overexpressing plants indicating that its role in aluminum signaling pathways, as previously observed for elicitor signaling, seems to be more complex than a simple negative regulator.

Although 12/15-lipoxygenase (12/15-LO) has been implicated as negative regulator of systemic bone mass in mice and humans, the underlying mechanisms remain elusive. Here, we show that 12/15-LO is a positive regulator of osteoclast (OC) development. Enzymatic inhibition as well as genetic ablation of 12/15-LO significantly impaired osteoclastogenesis. Conversely, addition of the 12/15-LO-derived eicosanoids 12- and 15-HETE augmented differentiation of precursors into fully matured OCs. Together these data point towards a crucial role of 12/15-LO in the regulation of OC development. Therefore, 12/15-LO and its human homologue 15-LO may display novel targets for the treatment of diseases such as osteoporosis and rheumatoid arthritis.

The nuclear factor-kappaB (NF-kappaB) and c-Jun NH2-terminal kinase (JNK) signaling pathways regulate diverse biological processes, including the immune and inflammatory response, cell growth, apoptosis, and tumour formation. Not surprisingly therefore defects to either pathway contributes to the progression of numerous human disorders. Enhancing our understanding of the mechanisms that control signaling through these pathways is therefore significant as it may enable development of specific treatments. In this regard, CYLD was recently identified as a negative regulator of NF-kappaB and JNK signaling. CYLD has a C-terminal catalytic domain characteristic of deubiquitinating enzymes, and this is essential for CYLD to remove ubiquitin from certain proteins that positively mediate signaling through the NF-kappaB and JNK pathways. Recent studies have revealed a requirement for CYLD in many different processes and have provided some insight into the underlying mechanisms.

Protein tyrosine phosphatase 1B (PTP 1B), a negative regulator of insulin receptor signaling system, has emerged as a highly validated, attractive target for the treatment of non-insulin dependent diabetes mellitus (NIDDM) and obesity. As a result there is a growing interest in the development of potent and specific inhibitors for this enzyme. This quantitative structure-activity relationship (QSAR) study for a series of formylchromone derivatives as PTP lB inhibitors was performed using genetic function approximation (GFA) technique. The QSAR models were developed using a training set of 29 compounds and the predictive ability of the QSAR model was evaluated against a test set of 7 compounds. The internal and external consistency of the final QSAR model was 0.766 and 0.785. The statistical quality of QSAR models was assessed by statistical parameters r2, r2 (crossvalidated r2), r2pred (predictive r2) and lack of fit (LOF) measure. The results indicate that PTP lB inhibitory activity of the formylchromone derivatives is strongly dependent on electronic, thermodynamic and shape related parameters.

The soluble Interleukin-6 receptor (sIL-6R) is capable of conferring the Interleukin-6 (IL-6) signal onto cells lacking the gp80 ligand binding protein. Here we investigate the release of sIL-6R from T-cells. After 2 h stimulation with PMA, a release of sIL-6R from peripheral human T-cells was observed which was insensitive to the protein synthesis inhibitor cycloheximide. This release was accompanied by a decrease of membrane-bound (mb) IL-6R. After 24 h, however, the observed sIL6-R release did prove to be sensitive to cycloheximide. These results suggest that both shedding and denovo-synthesis may be responsible for the PMA-induced sIL-6R release. In contrast to PMA, neither anti-CD3, a positive, nor IL-10, a negative regulator of IL-6 release from T-cells affected the production of the sIL-6R. The differential regulation of sIL-6R and IL-6 production by T-cells might be relevant for the immunomodulatory potential of the sIL-6R with respect to the interaction of T- and non-T-cells.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder marked by chorea, dystonia, incoordination, and cognitive and motor disturbance. The major cause of HD is the cytotoxicity of the mutant huntingtin protein (mHTT), encoded by the mutant HTT gene. The mechanism by which mHTT leads to cytotoxicity and neuronal death is unclear, and thus enhancing clearance of the mHTT protein is likely to be an effective approach to treat HD. We have recently identified NUB1 (negative regulator of ubiquitin-like proteins 1) as a modifier of mHTT levels via enhancement of its proteasomal degradation. In this review, we will discuss the mechanism of NUB1-mediated mHTT clearance and potential targeting

To ensure proper function, the tumor suppressor p53 is tightly regulated through different post-translational modifications, particularly ubiquitination. Recently, TRIM32 was identified as a p53-regulated gene and an E3 ubiquitin ligase of p53. Thus, TRIM32 and p53 form a novel auto-regulatory negative feedback loop for p53 regulation in cells.

Flowering is a developmental process, which is influenced by chemical and environmental stimuli. Recently, our research established that the Arabidopsis SUMO E3 ligase, AtSIZ1, is a negative regulator of transition to flowering through mechanisms that reduce salicylic acid (SA) accumulation and involve SUMO modification of FLOWERING LOCUS D (FLD). FLD is an autonomous pathway determinant that represses the expression of FLOWERING LOCUS C (FLC), a floral repressor. This addendum postulates mechanisms by which SIZ1-mediated SUMO conjugation regulates SA accumulation and FLD activity.

The small ubiquitin-related modifier (SUMO) E3 ligase SIZ1 is an ortholog of yeast and animal SIZ (SAP and Miz)/PIAS (protein inhibition of activated STAT) proteins, which function as transcriptional coregulators either by facilitating SUMO conjugation to substrate proteins (sumoylation) or through other mechanisms that are sumoylation independent. SIZ/PIAS-type E3 ligases function in numerous eukaryotic biological processes, including regulation of organismal responses to environmental changes. This addendum summarizes our recent paper in which it is established that the Arabidopsis E3 ligase SIZ1 mediates sumoylation of ICE1. SUMO conjugation to ICE1 facilitates ICE1 activity and stability that positively regulates CBF3/DREB1A-dependent cold signaling and freezing tolerance. Furthermore, sumoylated ICE1 represses MYB15, which is a negative regulator of CBF3/DREB1A and freezing tolerance.