Sucrose Non-fermenting 1-related Kinase Research Articles

Computational study of sucrose non-fermenting 1-related kinase 2 (SnRK2): An in-silico approach for homology modelling and structural characterization of drought related SAPK9 gene in rice (Oryza sativa L.)

Computational study of sucrose non-fermenting 1-related kinase 2 (SnRK2): An in-silico approach for homology modelling and structural characterization of drought related SAPK9 gene in rice (Oryza sativa L.)

HOS1 promotes plant tolerance to low-energy stress via the SnRK1 protein kinase.

Plants need to integrate internal and environmental signals to mount adequate stress responses. The NUCLEAR PORE COMPLEX (NPC) component HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1) is emerging as such an integrator, affecting responses to cold, heat, light, and salinity. Stress conditions often converge in a low-energy signal that activates SUCROSE NON-FERMENTING 1-RELATED KINASE 1 (SnRK1) to promote stress tolerance and survival. Here, we explored the role of HOS1 in the SnRK1-dependent response to low-energy stress in Arabidopsis thaliana, using darkness as a treatment and a combination of genetic, biochemical, and phenotypic assays. We show that the induction of starvation genes and plant tolerance to prolonged darkness are defective in the hos1 mutant. HOS1 interacts physically with the SnRK1α1 catalytic subunit in yeast two-hybrid assays and in planta, and the nuclear accumulation of SnRK1α1 is reduced in the hos1 mutant. Likewise, another NPC mutant, nup160, exhibits lower activation of starvation genes and decreased tolerance to prolonged darkness. Importantly, defects in low-energy responses in the hos1 background are rescued by fusing SnRK1α1 to a potent nuclear localization signal or by sugar supplementation during the dark treatment. Altogether, this work demonstrates the importance of HOS1 for the nuclear accumulation of SnRK1α1, which is key for plant tolerance to low-energy conditions.

RGA1 alleviates low-light-repressed pollen tube elongation by improving the metabolism and allocation of sugars and energy.

Low-light stress compromises photosynthetic and energy efficiency and leads to spikelet sterility; however, the effect of low-light stress on pollen tube elongation in the pistil remains poorly understood. The gene RGA1, which encodes a Gα-subunit of the heterotrimeric G-protein, enhanced low-light tolerance at anthesis by preventing the cessation of pollen tube elongation in the pistil of rice plants. In this process, marked increases in the activities of acid invertase (INV), sucrose synthase (SUS)and mitochondrial respiratory electron transport chain complexes, as well as the relative expression levels of SUTs (sucrose transporter), SWEETs (sugars will eventually be exported transporters), SUSs, INVs, CINs (cell-wall INV 1), SnRK1A (sucrose-nonfermenting 1-related kinase 1)and SnRK1B, were observed in OE-1 plants. Accordingly, notable increases in contents of ATP and ATPase were presented in OE-1 plants under low-light conditions, while they were decreased in d1 plants. Importantly, INV and ATPase activators (sucrose and Na2 SO3 , respectively) increased spikelet fertility by improving the energy status in the pistil under low-light conditions, and the ATPase inhibitor Na2 VO4 induced spikelet sterility and decreased ATPase activity. These results suggest that RGA1 could alleviate the low-light stress-induced impairment of pollen tube elongation to increase spikelet fertility by promoting sucrose unloading in the pistil and improving the metabolism and allocation of energy.

Molecular characterization reveals that OsSAPK3 improves drought tolerance and grain yield in rice

BackgroundMany data suggest that the sucrose non-fermenting 1-related kinases 2 (SnRK2s) are very important to abiotic stress for plants. In rice, these kinases are known as osmotic stress/ABA–activated protein kinases (SAPKs). Osmotic stress/ABA–activated protein kinase 3 (OsSAPK3) is a member of SnRK2II in rice, but its function is still unclear.ResultsThe expression of OsSAPK3 was up regulated by drought, NaCl, PEG and ABA. OsSAPK3 mutated seedings (sapk3-1 and sapk3-2) showed reduced hypersensitivity to exogenous ABA. In addition, under drought conditions, sapk3-1 and sapk3-2 showed more intolerance to drought, including decreased survival rate, increased water loss rate, increased stomatal conductance and significantly decreased expression levels of SLAC1 and SLAC7. Physiological and metabolic analyses showed that OsSAPK3 might play an important role in drought stress signaling pathway by affecting osmotic adjustment and osmolytes, ROS detoxification and expression of ABA dependent and independent dehydration-responsive genes. All gronomic traits analyses demonstrated that OsSAPK3 could improve rice yield by affecting the regulation of tiller numbers and grain size.ConclusionOsSAPK3 plays an important role in both ABA-dependent and ABA-independent drought stress responses. More interestingly, OsSAPK3 could improve rice yield by indirectly regulating tiller number and grain size. These findings provide new insight for the development of drought-resistant rice.

Genome-wide identification of sucrose non-fermenting-1-related protein kinase genes in maize and their responses to abiotic stresses.

Protein kinases play an important role in plants in response to environmental changes through signal transduction. As a large family of protein kinases, sucrose non-fermenting-1 (SNF1)-related kinases (SnRKs) were found and functionally verified in many plants. Nevertheless, little is known about the SnRK family of Zea mays. Evolutionary relationships, chromosome locations, gene structures, conserved motifs, and cis-elements in promoter regions were systematically analyzed. Besides, tissue-specific and stress-induced expression patterns of ZmSnRKs were determined. Finally, functional regulatory networks between ZmSnRKs and other proteins or miRNAs were constructed. In total, 60 SnRK genes located on 10 chromosomes were discovered in maize. ZmSnRKs were classified into three subfamilies (ZmSnRK1, ZmSnRK2, and ZmSnRK3), consisting of 4, 14, and 42 genes, respectively. Gene structure analysis showed that 33 of the 42 ZmSnRK3 genes contained only one exon. Most ZmSnRK genes contained at least one ABRE, MBS, and LTR cis-element and a few ZmSnRK genes had AuxRR-core, P-box, MBSI, and SARE ciselements in their promoter regions. The Ka:Ks ratio of 22 paralogous ZmSnRK gene pairs revealed that the ZmSnRK gene family had experienced a purifying selection. Meanwhile, we analyzed the expression profiles of ZmSnRKs, and they exhibited significant differences in various tissues and abiotic stresses. In addition, A total of eight ZmPP2Cs, which can interact with ZmSnRK proteins, and 46 miRNAs, which can target 24 ZmSnRKs, were identified. Generally, these results provide valuable information for further function verification of ZmSnRKs, and improve our understanding of the role of ZmSnRKs in the climate resilience of maize.

Negative feedback of SNRK to circ-SNRK regulates cardiac function post-myocardial infarction

A limited delivery of oxygen and metabolic substrate to the heart caused by myocardial infarction (MI) impairs the cardiac function, and often results in heart failure. Here, we identified a circRNA (circ-SNRK) from SNRK (sucrose nonfermenting 1-related kinase, which can increase the cardiac mitochondrial efficiency) in cardiomyocytes (CMs). Circ-SNRK can sponge the miR-33 and in turn improved the ATP synthesis via SNRK, proving the existence of circ-SNRK - miR-33 - SNRK axis. Furthermore, we found that protein NOVA1 (NOVA alternative splicing regulator 1) could accelerate the circ-SNRK formation; a cleaved peptide (~55 kDa) from SNRK enters the nucleus and blocks the cyclization of circ-SNRK via binding to NOVA1. The aforementioned negative feedback of SNRK to circ-SNRK limited the SNRK at a proper level, and inhibited the protective role of circ-SNRK in ischemic heart. In addition, our in vivo experiment indicated that the overexpression of exogenic circ-SNRK could break this loop and improves the cardiac function post-MI in rats. Together, our results demonstrated that the negative loop of circ-SNRK with SNRK regulates the energy metabolism in CMs, thus might be a potential therapeutic target for heart failure.

SAPK2 contributes to rice yield by modulating nitrogen metabolic processes under reproductive stage drought stress

BackgroundThe sucrose non-fermenting 1-related kinases 2 (SnRK2s) play important roles in osmotic stress responses in A. thaliana and rice (Oryza sativa L.). Osmotic stress/ABA–activated protein kinase 2 (SAPK2) is a member of SnRK2s subclass II in rice, but its function in rice yield under drought stress is unclear.ResultsCompared with wild-type (Oryza.Sativa L.spp.japonica, WT) plants, the sapk2 rice mutant lines were shorter and produced fewer grains per panicle, smaller grains and lower grain yield under reproductive stage drought stress (RDS). Subsequent analysis suggested that SAPK2 considerably influences the nitrogen, phosphorus, and potassium contents of rice grains. The examination of rice seedling growth and development under nutrient-deprived conditions (−N, −K, and − P) proved that SAPK2 can significantly affect rice seedling growth and root development in hydroponic cultures lacking N and K. Moreover, the NO3− influx rate and nitrate concentration analysis indicated that SAPK2 promotes nitrate uptake and assimilation by regulating nitrate-related transporters.ConclusionThese results suggest that SAPK2 could enhance grain production by regulating nitrogen utilization efficiency under RDS. Our work provided insights to breeding drought tolerant rice with high nutrient uptake.

SNRK: a metabolic regulator with multifaceted role in development and disease

Sucrose nonfermenting 1-related kinase (SNRK) is a serine/threonine kinase and a member of the adenosine monophosphate (AMP)-activated protein kinase (AMPK) family that is involved in the metabolic regulatory mechanisms in various cell types. SNRK is an important mediator in maintaining cellular metabolic homeostasis. In this review, we discuss the role of SNRK in metabolic tissues where it is expressed, including heart and adipose tissue. We discuss its role in regulating inflammation in these tissues and the pathways associated with regulating inflammation. We also discuss SNRK's role in vascular development and the processes associated with it. Finally, we review SNRK's potential as a target in various metabolic dysfunction-associated diseases such as cardiovascular diseases, diabetes, obesity, and cancer. This comprehensive review on SNRK suggests that it has therapeutic value in the suppression of inflammation in cardiac and adipose tissue.

Correction to: SNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In Vivo.

HomeArteriosclerosis, Thrombosis, and Vascular BiologyVol. 39, No. 9Correction to: SNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In Vivo Free AccessCorrectionPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCorrectionPDF/EPUBCorrection to: SNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In Vivo Originally published21 Aug 2019https://doi.org/10.1161/ATV.0000000000000085Arteriosclerosis, Thrombosis, and Vascular Biology. 2019;39:e209This article corrects the followingSNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In VivoIn the article by Lu et al, “SNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In Vivo,” which published in the February 2018 issue of the journal (Arterioscler Thromb Vasc Biol. 2018;38:373–385. doi: 10.1161/ATVBAHA.117.309834), a correction was needed.The labeling of the x-axis and the bar graph key were set incorrectly in Figure 5B and 5C. The errors do not affect the conclusion of this paper.The authors apologize for the errors.This correction has been made to the current online version of the article, which is available at www.ahajournals.org/doi/10.1161/ATVBAHA.117.309834. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesSNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In VivoQiulun Lu, et al. Arteriosclerosis, Thrombosis, and Vascular Biology. 2018;38:373-385 September 2019Vol 39, Issue 9 Advertisement Article InformationMetrics © 2019 American Heart Association, Inc.https://doi.org/10.1161/ATV.0000000000000085PMID: 31433694 Originally publishedAugust 21, 2019 PDF download Advertisement

Overexpression of the wheat trehalose 6-phosphate synthase 11 gene enhances cold tolerance in Arabidopsis thaliana

Low temperature is a key stress factor for the growth and development of wheat (Triticum aestivum L.), and glycometabolism plays an important role in plant cold tolerance. Our previous study identified trehalose 6-phosphate synthase 11 gene (TaTPS11), which had a significantly different expression pattern between a high freezing-tolerant wheat cultivar and a low freezing-tolerant wheat cultivar. In this study, TaTPS11 was isolated from a winter-hardy wheat cultivar (D1) and overexpressed in Arabidopsis thaliana to study its effect on cold tolerance in plants. Transgenic plants expressing TaTPS11 had lower sucrose content, higher starch content, and higher activity of key enzyme (sucrose phosphate synthase, sucrose synthase, and invertase) involved in sucrose metabolism. In addition, the expression level of sucrose non-fermenting 1-related kinase 1 (SnRK1), which catalyzes the sucrose in plants, increased in the TaTPS11-overexpressed plants. These results indicated that heterologous expression of TaTPS11 influenced carbohydrate metabolism in Arabidopsis plants. The resultant plants had a significantly higher survival rate after −5 °C treatment for 2 h and exhibited enhanced cold tolerance without unfavorable phenotypes compared to wild-type. Our findings indicated that manipulation of TaTPS11 improved cold tolerance in plants and TaTPS11 had potential values in wheat cold-tolerance breeding.

63 - Sucrose non-fermenting related kinase regulates cardiomyocyte protection during cardiac stress

Angiotensin II (Ang II), the key effector of the renin-angiotensin system (RAS) promotes the development of Dilated Cardiomyopathy (DCM), which ultimately leads to heart failure (HF). Previously, our lab has reported that a serine threonine kinase, Sucrose nonfermenting 1-related kinase (SNRK), a member of AMP-activated protein kinase (AMPK) family is critical for cardiac metabolism, and specific loss of SNRK in cardiomyocytes results in DCM. Thus, we hypothesize that, SNRK is involved in maintaining cardiac homeostasis and Ang II exacerbates cardiac dysfunction in cardiomyocyte-specific SNRK knockout mice (SNRK-CKO). To investigate this hypothesis, we performed ECHO on 4 months adult SNRK-CKO mice with and without Ang II, and found that most cardiac function parameters were compromised, followed by death in 14 days. These cardiac function defects were not observed in Ang II-infused SNRK-endothelial (EC) KO mice. We next investigated signaling pathways previously implicated in cardiac dysfunction. Indeed, upon stimulation with Ang II, the heart tissue shows downregulation of pERK and pJNK proteins and upregulation of pAKT protein. In contrast, in SNRK-ECKO, pERK and pJNK proteins were upregulated and pAKT protein was downregulated. Because pAKT, is known to increase inflammatory signaling pathways, in particular IKK-NF-κB, we investigated the IKK-NF-κB signaling in heart lysates from SNRK-CKO and SNRK-ECKO mice. Interestingly, we found upregulation of proinflammatory markers such as IL-6, TNFα and p65 NF-κB and downregulation of anti-inflammatory IL-10 in SNRK-CKO hearts only. This increase in inflammatory signaling is often followed by fibrosis, which was observed via Sirus Red staining for collagen accumulation in Ang II-infused SNRK-CKO hearts. At present, we are investigating the inflammatory and signaling pathways associated with lentivirus-mediated knockdown of SNRK in HL-1 cardiomyocytes in vitro. Overall, these results suggest that SNRK could be a potential target in regulating inflammatory mechanisms, which exerts cardioprotective effect in the heart.

SNRK (Sucrose Nonfermenting 1-Related Kinase) Promotes Angiogenesis In Vivo.

SNRK (sucrose nonfermenting 1-related kinase) is a novel member of the AMPK (adenosine monophosphate-activated protein kinase)-related superfamily that is activated in the process of angiogenesis. Currently, little is known about the function of SNRK in angiogenesis in the physiological and pathological conditions. In this study, in Snrk global heterozygous knockout mice, retina angiogenesis and neovessel formation after hindlimb ischemia were suppressed. Consistently, mice with endothelial cell (EC)-specific Snrk deletion exhibited impaired retina angiogenesis, and delayed perfusion recovery and exacerbated muscle apoptosis in ischemic hindlimbs, compared with those of littermate wide-type mice. Endothelial SNRK expression was increased in the extremity vessel samples from nonischemic human. In ECs cultured in hypoxic conditions, HIF1α (hypoxia inducible factor 1α) bound to the SNRK promoter to upregulate SNRK expression. In the nuclei of hypoxic ECs, SNRK complexed with SP1 (specificity protein 1), and together, they bound to an SP1-binding motif in the ITGB1 (β1 integrin) promoter, resulting in enhanced ITGB1 expression and promoted EC migration. Furthermore, SNRK or SP1 deficiency in ECs ameliorated hypoxia-induced ITGB1 expression and, consequently, inhibited EC migration and angiogenesis. Taken together, our data have revealed that SNRK/SP1-ITGB1 signaling axis promotes angiogenesis in vivo.

Abstract 1702: Sucrose nonfermenting 1-related kinase (SNRK) expression in ovarian cancer and correlation with clinical features

Abstract Objective: Human omental adipocytes promote migration and invasion of ovarian cancer cells and result in alterations in metabolism including increased AMP-activated protein kinase (AMPK) and b-oxidation, which allow for use of lipids as an energy source. Sucrose nonfermenting 1-related kinase (SNRK) is a member of the AMPK family of serine/threonine kinases, which are activated by starvation and stress conditions. The goal of this study is to describe the expression of SNRK in human ovarian cancer tissue. Methods: Tissue was collected from patients undergoing surgery for serous ovarian cancer or benign indications. Immunohistochemistry (IHC) was used to detect SNRK expression. SNRK+ cells were compared between benign and malignant tissue, and statistical significance between positivity and clinicopathologic variables was determined using the Mann-Whitney U test. Results: In the 31 samples analyzed, SNRK demonstrates a nuclear staining pattern. IHC shows increased SNRK+ cells in malignant tissue versus benign tissue (42.0% versus 31.3% positive nuclei, p<0.001). When examining patient characteristics, the malignant samples with the lowest percentage of SNRK+ nuclei were stage IIIB-IV with a high incidence of recurrence and death due to disease. Conclusions: This is the first study to describe SNRK expression in ovarian cancer tissue. We show that SNRK has a nuclear staining pattern and that expression is greater in malignant ovarian tissue compared to benign ovarian tissue, which may be due to more metabolic stress on cells with higher proliferation rates. SNRK expression appears to be lower in those with a higher disease stage and poor outcome potentially secondary to metabolic changes that occur once the disease metastasizes. We are currently examining SNRK expression in metastatic omental tumors in order to further explore expression differences between primary versus metastatic disease sites. Citation Format: Elizabeth E. Hopp, Erin Bishop, Stephanie Cossette, Ramani Ramchandran. Sucrose nonfermenting 1-related kinase (SNRK) expression in ovarian cancer and correlation with clinical features. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1702.

The sucrose non-fermenting 1-related kinase 2 gene SAPK9 improves drought tolerance and grain yield in rice by modulating cellular osmotic potential, stomatal closure and stress-responsive gene expression.

BackgroundFamily members of sucrose non-fermenting 1-related kinase 2 (SnRK2), being plant-specific serine/threonine protein kinases, constitute the central core of abscisic acid (ABA)-dependent and ABA-independent signaling pathways, and are key regulators of abiotic stress adaptation in plants. We report here the functional characterization of SAPK9 gene, one of the 10 SnRK2s of rice, through developing gain-of-function and loss-of-function phenotypes by transgenesis.ResultsThe gene expression profiling revealed that the abundance of single gene-derived SAPK9 transcript was significantly higher in drought-tolerant rice genotypes than the drought-sensitive ones, and its expression was comparatively greater in reproductive stage than the vegetative stage. The highest expression of SAPK9 gene in drought-tolerant Oryza rufipogon prompted us to clone and characterise the CDS of this allele in details. The SAPK9 transcript expression was found to be highest in leaf and upregulated during drought stress and ABA treatment. In silico homology modelling of SAPK9 with Arabidopsis OST1 protein showed the bilobal kinase fold structure of SAPK9, which upon bacterial expression was able to phosphorylate itself, histone III and OsbZIP23 as substrates in vitro. Transgenic overexpression (OE) of SAPK9 CDS from O. rufipogon in a drought-sensitive indica rice genotype exhibited significantly improved drought tolerance in comparison to transgenic silencing (RNAi) lines and non-transgenic (NT) plants. In contrast to RNAi and NT plants, the enhanced drought tolerance of OE lines was concurrently supported by the upgraded physiological indices with respect to water retention capacity, soluble sugar and proline content, stomatal closure, membrane stability, and cellular detoxification. Upregulated transcript expressions of six ABA-dependent stress-responsive genes and increased sensitivity to exogenous ABA of OE lines indicate that the SAPK9 is a positive regulator of ABA-mediated stress signaling pathways in rice. The yield-related traits of OE lines were augmented significantly, which resulted from the highest percentage of fertile pollens in OE lines when compared with RNAi and NT plants.ConclusionThe present study establishes the functional role of SAPK9 as transactivating kinase and potential transcriptional activator in drought stress adaptation of rice plant. The SAPK9 gene has potential usefulness in transgenic breeding for improving drought tolerance and grain yield in crop plants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0845-x) contains supplementary material, which is available to authorized users.

Abstract B57: Sucrose nonfermenting 1-related kinase (SNRK) expression and function in ovarian cancer.

Abstract Purpose of study: SNRK is a member of the sucrose nonfermenting (SNF)-related kinase family of serine/threonine kinases with sequence similarity to AMP-activated protein kinase (AMPK). AMPK proteins play a central role in cellular energy regulation. Active AMPK restricts cellular proliferation, growth, and metabolic substrate synthesis, and increases ATP-generating processes, such as glucose and fatty acid oxidation. SNKR has been previously shown to regulate metabolism and to suppress adipocyte inflammation via mTORC1, which is a pathway known to be aberrant in ovarian cancer. SNRK has also been shown to reduce colon cancer cell proliferation and stable knockdown of SNRK increases in vitro colon cancer cell tumorigenicity indicating that SNRK is a regulator of cell proliferation. The goal of this study is to describe the expression and function of SNRK in ovarian cancer and benign cell lines. Experimental Procedures: The ovarian cancer cell line A2780 was used as well as the benign surface epithelial cell line, IOSE, for comparison. Quantitative PCR and western blot analysis were used to compare SNRK mRNA and protein expression between cell lines. SNRK was knocked down in each cell line using lentiviral transduction. Proliferation, migration, and invasion assays were performed to determine the effects of SNRK knockdown on tumorigenicity. Alterations in metabolism as a result of SNRK knockdown were assessed using the XF Extracellular Flux Analyzer (Seahorse Bioscience). Western blot analysis was used to determine changes in active phosphorylated AMPK (pAMPK) and mTOR protein expression. Summary of data: IOSE and A2780 cells have similar levels of SNRK mRNA and protein expression. We observed increased proliferation, migration, and invasion in SNRK knockdown cells compared to controls with significant differences seen in the IOSE cells. A2780 and IOSE SNRK knockdown cells have decreased oxygen consumption rates and decreased spare respiratory capacity in the presence of fatty acids as a substrate compared to controls as well as decreased pAMPK and mTOR expression. Conclusions: Our results show that decreased SNRK levels lead to increased tumorigenicity and impairment in fatty acid oxidation particularly in the benign IOSE cells. Along with these functional changes, a decrease in pAMPK expression is also seen. Our results suggest that SNRK plays a role in regulating growth and metabolism and that this regulation appears to be required in benign ovarian cells, while malignant cells may have the ability to control growth independent of SNRK. Citation Format: Erin A. Bishop, Stephanie M. Cossette, Ramani Ramchandran. Sucrose nonfermenting 1-related kinase (SNRK) expression and function in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr B57.

Abstract POSTER-BIOL-1302: Sucrose nonfermenting 1-related kinase (SNRK) expression and function in vitro in ovarian cancer cells

Abstract Purpose of study: Lipid metabolism and transport have recently been identified as potential targets for the treatment of cancers where adipocytes are a major component of the tumor microenvironment. Ovarian cancer metastases have a clear predilection for the omentum, which is primarily comprised of adipocytes. Studies have shown that human omental adipocytes promote migration and invasion of ovarian cancer cells and that adipocyte–ovarian cancer cell coculture promotes tumor growth and induces lipolysis in adipocytes and β-oxidation in cancer cells. SNRK is a serine/threonine kinase with sequence similarity to AMP-activated protein kinase (AMPK). AMPK proteins play a central role in cellular energy regulation. Active AMPK restricts cell proliferation, cell growth, and metabolic substrate synthesis, and increases ATP-generating processes, such as glucose and fatty acid oxidation. It has also been suggested that SNRK suppresses adipocyte inflammation via mTORC1 which is a pathway known to be aberrant in ovarian cancer. SNRK has been shown to reduce colon cancer cell proliferation and DNA synthesis and SNRK levels are decreased in human colon cancer tissue. Stable knockdown of SNRK increases in vitro colon cancer cell tumorigenicity indicating that SNRK is a regulator of cell proliferation. Because of the role SNRK appears to play in cell proliferation and metabolism and the link between SNRK and mTORC1 signaling, the goal of this study is to describe expression of SNRK in ovarian cancer cell lines and ovarian tissue from mice. Experimental Procedures: The ovarian cancer cell lines A2780 and SKOV3ip1 as well as a normal surface epithelial cell line IOSE, were grown in culture media and then immunostained for SNRK, as well as CC3 (apoptosis) and PH3 (proliferation). To assess the expression of SNRK in mice, ovarian tissue from wild type mice were harvested and immunostained for SNRK. Summary of data: Cell line immunostaining demonstrated differential expression of SNRK in both ovarian cancer cell lines and the benign ovarian epithelial cell line along with PH3 staining. There was no CC3 staining seen in any of the cell lines. The mouse ovarian tissue shows SNRK staining in the nuclei of follicular cells but no clear staining in the epithelial or stromal cells. Conclusions: Our results show the presence of SNRK in both benign and malignant epithelial ovarian cell lines as well as in benign mouse ovarian tissue. We plan to further explore SNRK expression levels in ovarian cancer by quantifying SNRK mRNA and protein levels in ovarian cancer cell lines as well as in human benign and malignant ovarian tissue. We also plan to knockdown SNRK expression in ovarian cancer cell lines to determine effects on cell proliferation, migration, and invasion as well as changes in proteins involved in proliferation and metabolism. Citation Format: Erin Bishop, Stephanie Cossette, Vakeel Padmanabhan, Ramani Ramchandran. Sucrose nonfermenting 1-related kinase (SNRK) expression and function in vitro in ovarian cancer cells [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1302.

Identification of salt-tolerant barley varieties by a consolidated physiological and molecular approach

Soil salinity is a significant international environmental problem and severely affects the yield of cereal crops due to numerous effects on plant–water relations, ion homeostasis and salt toxicity. This work assessed the salt tolerance levels of 16 barley varieties by key physiological and molecular tests. Seedlings were exposed to acute salinity stress and their physiological responses including relative water content, levels of the stress hormone abscisic acid (ABA) and Na+/K+ ratio were compared. A significant variation was noted amongst the varieties, with Calmariout, Hindmarsh and Mundah identified as tolerant varieties and Franklin as the most sensitive variety. Further, the differential expression of key genes in the ABA-regulated stress response pathway, i.e., pyrabactin resistance (PYR)/PYR-Like (PYL)/regulatory components of ABA receptors (RCAR), protein phosphatase 2C (PP2C), sucrose non-fermenting 1-related kinase (SnRK2) and specific ABC transporters, was analysed by quantitative real-time PCR of leaf RNA. The PP2CA and ABC transporters were up-regulated while the PYR/PYL/RCARs and SnRK2s were down-regulated under salt stress. Importantly, tolerance ranking by gene expression closely correlated that by physiological indices. Thus expression analysis of the ABA pathway may be used for rapid identification of potentially salt-tolerant barley varieties before undertaking physiological studies. The outcomes are relevant for varietal selection and comparing the alleles for genetics of tolerance.

Arabidopsis CIPK14 positively regulates glucose response

Calcium is a ubiquitous intracellular secondary messenger in plants. Calcineurin B-like proteins (CBLs), which contain four Ca2+-binding EF hand motifs, are Ca2+ sensors and regulate a group of Ser/Thr protein kinases called CBL-interacting protein kinases (CIPKs). Although the CBL–CIPK network has been demonstrated to play crucial roles in plant development and responses to various environmental stresses in Arabidopsis, little is known about their function in glucose signaling.In the present study, we identified CIPK14 gene from Arabidopsis that play a role in glucose signaling. The subcellular localization of CIPK14 was determined using green fluorescence protein (GFP) as the reporter. Furthermore, the expression levels of CIPK14 in response to salt, drought, cold, heat, ABA, methyl viologen (MV) and glucose treatments were examined by quantitative RT-PCR and it was found to respond to multiple stimuli, suggesting that CIPK14 may be a point of convergence for several different signaling pathways. Moreover, knock-out mutation of CIPK14 rendered it more sensitive to glucose treatment. Yeast two-hybrid assay demonstrated that CIPK14 interacted with three CBLs and also with two key kinases, sucrose non-fermenting 1-related kinase (SnRK) 1.1 and SnRK1.2 implicated in glucose signaling. This is the first report to demonstrate that CIPK also plays a role in glucose signaling.

Interaction of SOS2 with Nucleoside Diphosphate Kinase 2 and Catalases Reveals a Point of Connection between Salt Stress and H2O2 Signaling in Arabidopsis thaliana

SOS2, a class 3 sucrose-nonfermenting 1-related kinase, has emerged as an important mediator of salt stress response and stress signaling through its interactions with proteins involved in membrane transport and in regulation of stress responses. We have identified additional SOS2-interacting proteins that suggest a connection between SOS2 and reactive oxygen signaling. SOS2 was found to interact with the H2O2 signaling protein nucleoside diphosphate kinase 2 (NDPK2) and to inhibit its autophosphorylation activity. A sos2-2 ndpk2 double mutant was more salt sensitive than a sos2-2 single mutant, suggesting that NDPK2 and H2O2 are involved in salt resistance. However, the double mutant did not hyperaccumulate H2O2 in response to salt stress, suggesting that it is altered signaling rather than H2O2 toxicity alone that is responsible for the increased salt sensitivity of the sos2-2 ndpk2 double mutant. SOS2 was also found to interact with catalase 2 (CAT2) and CAT3, further connecting SOS2 to H2O2 metabolism and signaling. The interaction of SOS2 with both NDPK2 and CATs reveals a point of cross talk between salt stress response and other signaling factors including H2O2.

Identification of protein kinase SNF1 in CitEST

SnRKs (Sucrose non-fermenting-1 related kinases) is a family of protein kinases found in many crops, such as Arabidopsis, rice, sugarcane, tomato and several other plant species. This family of proteins is also present in other organisms like Saccharomyces cerevisiae (sucrose non-fermenting-1 - Snf1) and in mammals (AMP-activated protein kinases - AMPKs). There is evidence that SnRKs play an important role in plant responses to nutritional and environmental stresses and that SnRKs also play a major role in controlling key enzymes in the biosynthetic pathways of plants. In this work, we identified 18 contigs and two singletons encoding putative SnRKs in the CitEST database. All of them present highly conserved N-terminal catalytic domain, which is found in the SnRKs families of several plant species. Through comparison with known SnRKs, we were able to classify them into three subfamilies.