• Molecules and Cells
• /
• v.42 no.10
• /
• pp.693-701
• /
• 2019

Plants monitor changes in day length to coordinate their flowering time with appropriate seasons. In Arabidopsis, the diel and seasonal regulation of CONSTANS (CO) protein stability is crucial for the induction of FLOWERING LOCUS T (FT) gene in long days. FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) and ZEITLUPE (ZTL) proteins control the shape of CO expression profile antagonistically, although regulation mechanisms remain unknown. In this study, we show that GIGANTEA (GI) protein modulates the stability and nuclear function of FKF1, which is closely related to the stabilization of CO in the afternoon of long days. The abundance of FKF1 protein is decreased by the gi mutation, but increased by GI overexpression throughout the day. Unlike the previous report, the translocation of FKF1 to the nucleus was not prevented by ZTL overexpression. In addition, the FKF1-ZTL complex formation is higher in the nucleus than in the cytosol. GI interacts with ZTL in the nucleus, implicating the attenuation of ZTL activity by the GI binding and, in turn, the sequestration of FKF1 from ZTL in the nucleus. We also found that the CO-ZTL complex presents in the nucleus, and CO protein abundance is largely reduced in the afternoon by ZTL overexpression, indicating that ZTL promotes CO degradation by capturing FKF1 in the nucleus under these conditions. Collectively, our findings suggest that GI plays a pivotal role in CO stability for the precise control of flowering by coordinating balanced functional properties of FKF1 and ZTL.

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2003.04a
• /
• pp.130-130
• /
• 2003

• Biomolecules & Therapeutics
• /
• v.23 no.6
• /
• pp.539-548
• /
• 2015

Prostaglandin $E_2$ ($PGE_2$), a major product of cyclooxygenase, binds to four different prostaglandin $E_2$ receptors (EP1, EP2, EP3, and EP4) which are G-protein coupled transmembrane receptors (GPCRs). Although GPCRs including EP receptors have been shown to be associated with their specific G proteins, recent evidences suggest that GPCRs can regulate MAPK signaling via non-G protein coupled pathways including Src. EP2 is differentially expressed in various tissues and the expression of EP2 is induced by extracellular stimuli. We hypothesized that an increased level of EP2 expression may affect MAPK signaling. The overexpression of EP2 in HEK 293 cells resulted in significant increase in intracellular cAMP levels response to treatment with butaprost, a specific EP2 agonist, while overexpression of EP2 alone did not increase intracellular cAMP levels. However, EP2 overexpression in the absence of $PGE_2$ induced an increase in the level of p38 phosphorylation as well as the kinase activity of p38, suggesting that up-regulation of EP2 may promote p38 activation via non-G protein coupled pathway. Inhibition of Src completely blocked EP2-induced p38 phosphorylation and overexpression of Src increased the level of p38 phosphorylation, indicating that Src is upstream kinase for EP2-induced p38 phosphorylation. EP2 overexpression also increased the Src activity and EP2 protein was co-immunoprecipitated with Src. Furthermore, sequential co-immunoprecipitation studies showed that EP2, Src, and ${\beta}$-arrestin can form a complex. Our study found a novel pathway in which EP2 is associated with Src, regulating p38 pathway.

• Journal of Life Science
• /
• v.20 no.9
• /
• pp.1314-1323
• /
• 2010

In this study, we constructed various kinds of binary vectors with the pPZP backbone for co-overexpression, tissue- or development-specific expression and stress-inducible expression, and validated them for ectopic expression of target genes. Using a modified CaMV 35S promoter, a binary vector was generated for co-overexpression of two different genes and was confirmed to be efficient for overexpressing two different target genes at the same time and place. Binary vectors containing At2S3, KNAT1 or LFY promoters were constructed for tissue-specific or development-specific gene expression, and the binary vectors were suited for embryo/young seedling stage-, shoot apical meristem- or leaf primordia-specific expressions. Furthermore, the binary vectors containing RD29A or AtNCED3 promoters were validated as suitable vectors for gene expression induced by abiotic stresses such as high salt, ABA, MV and low temperature. Taken together, the binary vectors constructed in this study would be very useful for analyzing the biological functions of target genes and molecular mechanisms through ectopic expression.

• Animal cells and systems
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2011

Perturbation of metabolism with increased expression of lipogenic enzymes is a common characteristic of human cancers, including prostate cancer. In the present work the overexpression of stearoyl-CoA desaturase (SCD) in LNCaP cells led to increased mRNA levels of fatty acid synthase (FAS) and acetyl-CoA-carboxylase-a, whereas micro RNA-mediated silencing of SCD inhibited the expression of these lipogenic genes in LNCaP cells. Treatment with the FAS-specific inhibitor cerulenin inhibited SCD induction of LNCaP cell proliferation. In addition, a transient transfection assay revealed the capability of cerulenin to suppress SCD and dihydrotestosterone induction of androgen receptor transcriptional activity. Furthermore, overexpression of SCD in LNCaP cells produced marked resistance to ceramide-induced cell death with reduced poly(ADP-ribose) polymerase (PARP) cleavage. In contrast, silencing of SCD expression increased Bax protein in LNCaP cells. Furthermore, addition of ceramide to SCD knockdown LNCaP cells increased cell death and caspase-3 activity with drastic increase of PARP cleavage. Together, the data indicate that SCD may provide resistance of prostate cancer cells to ceramide-induced cell death.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.6
• /
• pp.3847-3850
• /
• 2013

The three homologous members of the p160 SRC family (SRC-1, SRC-2 and SRC-3) mediate the transcriptional functions of nuclear receptors and other transcription factors, and are the most studied of all the transcriptional co-activators. Recent work has indicated that the SRC-3 gene is subject to amplification and overexpression in various human cancers. Some of the molecular mechanisms responsible for SRC overexpression, along with the mechanisms by which SRC-3 promotes breast and prostate cancer cell proliferation and survival, have been identified. However, the function of SRC-3 in bladder cancer remains poorly understood. In the present study, our results indicate that overexpression of SRC-3 promotes bladder cancer cell proliferation whereas knockdown of SRC-3 results in inhibition. At the molecular level, we further established that CXCR4 is a transcriptional target of SRC-3. Therefore, our study first identified that SRC-3 plays a critical role in the bladder cancer, which may be a target beneficial for its prevention and treatment.

• Molecules and Cells
• /
• v.26 no.4
• /
• pp.368-372
• /
• 2008

Recent molecular and genetic studies in rice, a short-day plant, have elucidated both conservation and divergence of photoperiod pathway genes and their regulators. However, the biological roles of rice genes that act within the autonomous pathway are still largely unknown. In order to better understand the function of the autonomous pathway genes in rice, we conducted molecular genetic analyses of OsFVE, a rice gene homologous to Arabidopsis FVE. OsFVE was found to be ubiquitously expressed in vegetative and reproductive organs. Overexpression of OsFVE could rescue the flowering time phenotype of the Arabidopsis fve mutants by up-regulating expression of the SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) and down-regulating FLOWERING LOCUS C (FLC) expression. These results suggest that there may be a conserved function between OsFVE and FVE in the control of flowering time. However, OsFVE overexpression in the fve mutants did not rescue the flowering time phenotype in in relation to the response to intermittent cold treatment.

• The Korean Journal of Physiology and Pharmacology
• /
• v.24 no.3
• /
• pp.203-212
• /
• 2020

Promyelocytic leukemia (PML) gene, through alternative splicing of its C-terminal region, generates several PML isoforms that interact with specific partners and perform distinct functions. The PML protein is a tumor suppressor that plays an important role by interacting with various proteins. Herein, we investigated the effect of the PML isoforms on oncostatin M (OSM)-induced signal transducer and activator of transcription-3 (STAT-3) transcriptional activity. PML influenced OSM-induced STAT-3 activity in a cell type-specific manner, which was dependent on the p53 status of the cells but regardless of PML isoform. Interestingly, overexpression of PML exerted opposite effects on OSM-induced STAT-3 activity in p53 wild-type and mutant cells. Specifically, overexpression of PML in the cell lines bearing wild-type p53 (NIH3T3 and U87-MG cells) decreased OSM-induced STAT-3 transcriptional activity, whereas overexpression of PML increased OSM-induced STAT-3 transcriptional activity in mutant p53-bearing cell lines (HEK293T and U251-MG cells). When wild-type p53 cells were co-transfected with PML-IV and R273H-p53 mutant, OSM-mediated STAT-3 transcriptional activity was significantly enhanced, compared to that of cells which were transfected with PML-IV alone; however, when cells bearing mutant p53 were co-transfected with PML-IV and wild-type p53, OSM-induced STAT-3 transcriptional activity was significantly decreased, compared to that of transfected cells with PML-IV alone. In conclusion, PML acts together with wild-type or mutant p53 and influences OSM-mediated STAT-3 activity in a negative or positive manner, resulting in the aberrant activation of STAT-3 in cancer cells bearing mutant p53 probably might occur through the interaction of mutant p53 with PML.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.243.2-244
• /
• 2002

Protein-tyrosine phosphatases (PTPs) constitute a family of receptor-like and cytoplasmic enzymes. which catalyze the dephosphorylation of phosphotyrosine residues in a variety of receptors and signaling molecules. Thirty subtypes of PTPs have been identified in human genomes. Among PTPs, PTP1 B has been suggested as a negative regulator of insulin signaling. Overexpression of this enzyme has been known as a cause of obesity and type II diabetes, so it is a target for drug discovery. (omitted)

• Nutrition Research and Practice
• /
• v.10 no.4
• /
• pp.377-384
• /
• 2016

BACKGROUND/OBJECTIVES: Resveratrol, a natural polyphenol, has multiple functions in cellular responses including apoptosis, survival, and differentiation. It also participates in the regulation of inflammatory response and oxidative stress. MicroRNA-Let-7A (miR-Let7A), known as a tumor suppressor miRNA, was recently reported to play a crucial role in both inflammation and apoptosis. Therefore, we examined involvement of miR-Let7A in the modulation of inflammation and cell survival/apoptosis regulated by resveratrol. MATERIALS/METHODS: mRNA expression of pro-/anti-inflammatory cytokines and sirtuin 1 (SIRT1), and protein expression of apoptosis signal-regulating kinase 1 (ASK1), p-ASK1, and caspase-3 and cleaved caspase-3 were measured, and cell viability and Hoechst/PI staining for apoptosis were observed in Lipopolysaccharide (LPS)-stimulated human THP-1 macrophages with the treatment of resveratrol and/or miR-Let7A overexpression. RESULTS: Pre-treatment with resveratrol ($25-200{\mu}M$) resulted in significant recovery of the reduced cell viabilities under LPS-induced inflammatory condition and in markedly increased expression of miR-Let7A in non-stimulated or LPS-stimulated cells. Increased mRNA levels of tumor necrosis $factor-{\alpha}$ and interleukin (IL)-6 induced by LPS were significantly attenuated, and decreased levels of IL-10 and brain-derived neurotrophic factor were significantly restored by resveratrol and miR-Let7A overexpression, respectively, or in combination. Decreased expression of IL-4 mRNA by LPS stimulation was also significantly increased by miR-Let7A overexpression co-treated with resveratrol. In addition, decreased SIRT1 mRNA levels, and increased p-ASK1 levels and PI-positive cells by LPS stimulation were significantly restored by resveratrol and miR-Let7A overexpression, respectively, or in combination. CONCLUSIONS: miR-Let7A may be involved in the inflammatory response and cell survival/apoptosis modulated by resveratrol in human THP-1 macrophages.