• Title/Summary/Keyword: functional role

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Aequorin Based Functional Assessment of the Melanin Concentrating Hormone Receptor by Intracellular Calcium Mobilization

  • Lee, Sung-Hou
    • Biomolecules & Therapeutics
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    • v.18 no.2
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    • pp.152-158
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    • 2010
  • Melanin concentrating hormone is a neuropeptide highly expressed in the brain that regulates several physiological functions mediated by receptors in the G-protein coupled receptor family, especially plays an important role in the complex regulation of energy balance and body weight mediated by the melanin concentrating hormone receptor subtype 1 (MCH1). Compelling pharmacological evidence implicating MCH1 signaling in the regulation of food intake and energy expenditure has generated a great deal of interest by pharmaceutical companies as MCH1 antagonists may have potential therapeutic benefit in the treatment of obesity and metabolic syndrome. Although fluorescence-based calcium mobilization assay platform has been one of the most widely accepted tools for receptor research and drug discovery, fluorescence interference and shallow assay window limit their application in high throughput screening and have led to a growing interest in alternative, luminescence-based technologies. Herein, a luminescence-based functional assay system for the MCH1 receptor was developed and validated with the mitochondrial targeted aequorin. Aequorin based functional assay system for MCH1 presented excellent Z' factor (0.8983) and high signal-to-noise ratio (141.9). The nonpeptide MCH1 receptor antagonist, SNAP 7941 and GSK 803430, exhibited $IC_{50}$ values of 0.62 ${\pm}$ 0.11 and 12.29 ${\pm}$ 2.31 nM with excellent correlation coefficient. These results suggest that the aequorin based assay system for MCH1 is a strong alternative to the traditional GPCR related tools such as radioligand binding experiments and fluorescence functional determinations for the compound screening and receptor research.

Functional Expression and Characterization of C-terminal Mutant of 4-Aminobutyrate Aminotransferase

  • Sung, Bo-Kyung;Cho, Jung-Jong;Kim, Young-Tae
    • BMB Reports
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    • v.32 no.2
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    • pp.181-188
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    • 1999
  • 4-Aminobutyrate aminotransferase plays an essential role in the 4-aminobutyric acid shunt, converting 4-aminobutyrate to succinic semialdehyde. Recombinant 4-aminobutyrate aminotransferases were overexpressed as their catalytically active forms in E. coli by coproduction with thioredoxin and their solubilities were also dramatically increased. In order to study the structural and functional aspects of the C-terminal domain of brain 4-aminobutyrate aminotransferase, we have constructed a C-terminal mutant of pig brain 4-aminobutyrate aminotransferase and analyzed the functional and structural roles of C-terminal amino acids residues on the enzyme. The deletion of five amino-acid residues from C-terminus did not interfere with the kinetic parameters and functional properties of the enzyme. Also, the deletion did not affect the dimeric structure of the protein aligned along the subunit interface at neutral pH. However, the deletion of the C-terminal region of the protein changed the stability of its dimeric structure at acidic pH. The dissociation of the enzyme acidic, facilitated by the deletion of five amino acids from C-terminus, abolished the catalytic activity.

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Structural and Functional relationship of the recombinant catalytic subunit of pyruvate dehydrogenase phosphatase

  • Kim, Young-Mi;Jung, Ki-Hwa
    • Proceedings of the Korean Society of Food Hygiene and Safety Conference
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    • 2002.05a
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    • pp.215-215
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    • 2002
  • Catalytic subunit of pyruvate dehydrogenase phosphatase (PDPc) has been suggested to have three major funational domains such as dihydrplipoamide adetyltransferase(E2)-binding domain, regulatory subunit of PDP(PDP)r-binding domain, and calcium-binding domain. In order to identify functional domains, recombinant catalytic subunit of pyruvate dehydrogenase phosphatase(rPDPc) was expressed in E. coli JM101 and purified to near homogeneity using the unique property of PDPc: PDPc binds to the inner lipoyl domain (L2) of E2 of ppyruvate dehydrogenase complex (PDC) in the presence of Ca+2, not under EGTA. PDPc was limited-proteolysed by typsin, chymotypsin, Arg-C, and elastase at pH 7.0 and 30C and N-terminal analysis of the fragments was done. Chymotrypsin, trypsin, and elastase made two major fragments: N-terminal large fragment, approx. 50kD and C-terminal small fragment, approx.10 kDa. Arg-C made three major fragments: N-terminal fragment, approx. 35kD, and central fragment, approx. 15 kD, and C-terminal fragment, approx. 10 kD. This study strongly suggest that PDPc consists of three major functional domains. However, further study should be necessary to identify the functional role.

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Comparative Analyses of Flavonoids for nod Gene Induction in Bradyrhizobium japonicum USDA110

  • RYU JI-YOUNG;HUR HOR-GIL
    • Journal of Microbiology and Biotechnology
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    • v.15 no.6
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    • pp.1280-1285
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    • 2005
  • Using the nodY::lacZ fusion system in Bradyrhizobium japonicum USDA 110, 22 flavonoids, which have structurally different features, were tested to define the role of the substituted functional groups as an inducer or inhibitor for the nod gene expression. A functional ,group of 4'-OH on the B-ring and the double bond between 2-C and 3-C on the C ring were required to induce the nod gene expression in B. japonicum USDA 110. In the case of isoflavones, the 4'-methoxyl group, which blocks the open 4'-OH functional group, did not significantly lower inducing activity, as compared with isoflavones with 4'-OH. However, all flavonols tested, which have a 3-OH functional group on the C-ring, did not induce, but inhibited the nod gene expression. Flavone, 7-hydroxyflavone, and kaempferol (5,7,4'-trihydroxyflavonol) at $1\;{\mu}M$ concentration significantly inhibited the nod gene expression induced by 7,4'-dihydroxyflavone. However, 7-hydroxy-4'-methoxyflavone at $1\;{\mu}M$ concentration showed a synergistic effect with genistein and 7,4'-dihydroxyflavone on the induction activity.

Nuclear Localization of Chfr Is Crucial for Its Checkpoint Function

  • Kwon, Young Eun;Kim, Ye Seul;Oh, Young Mi;Seol, Jae Hong
    • Molecules and Cells
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    • v.27 no.3
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    • pp.359-363
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    • 2009
  • Chfr, a checkpoint with FHA and RING finger domains, plays an important role in cell cycle progression and tumor suppression. Chfr possesses the E3 ubiquitin ligase activity and stimulates the formation of polyubiquitin chains by Ub-conjugating enzymes, and induces the proteasome-dependent degradation of a number of cellular proteins, including Plk1 and Aurora A. While Chfr is a nuclear protein that functions within the cell nucleus, how Chfr is localized in the nucleus has not been clearly demonstrated. Here, we show that nuclear localization of Chfr is mediated by nuclear localization signal (NLS) sequences. To reveal the signal sequences responsible for nuclear localization, a short lysine-rich stretch (KKK) at amino acid residues 257-259 was replaced with alanine, which completely abolished nuclear localization. Moreover, we show that nuclear localization of Chfr is essential for its checkpoint function but not for its stability. Thus, our results suggest that NLS-mediated nuclear localization of Chfr leads to its accumulation within the nucleus, which may be important in the regulation of Chfr activation and Chfr-mediated cellular processes, including cell cycle progression and tumor suppression.

Immunohistochemical localization of galectin-3 in the brain with Theiler's murine encephalomyelitis virus (DA strain) infection

  • Shin, Taekyun;Carrillo-Salinas, Francisco J.;Martinez, Ana Feliu;Mecha, Miriam;Guaza, Carmen
    • Korean Journal of Veterinary Research
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    • v.53 no.3
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    • pp.159-162
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    • 2013
  • Galectin-3 is a ${\beta}$-galactoside-binding lectin that plays a role in neuroinflammation through cell migration, proliferation, and apoptosis. In the present study, regulation of galectin-3 was examined in the brain of mice infected with the Daniel strain of Theiler's murine encephalomyelitis virus (TMEV) at days 7 and 81 post-infection by immunohistochemistry. Immunohistochemistry revealed that galectin-3 was mainly localized in ionized calcium-binding adapter 1-positive macrophages/activated microglia, but not in Iba-1-positive ramified microglia. Galectin-3 was also weakly detected in some astrocytes in the same encephalitic lesions, but not in neurons and oligodendrocytes. Collectively, the present findings suggest that galectin-3, mainly produced by activated microglia/macrophages, may be involved in the pathogenesis of virus induced acute inflammation in the early stage as well as the chronic demyelinating lesions in Daniel strain of TMEV induced demyelination model.

Autophagy and Digestive Disorders: Advances in Understanding and Therapeutic Approaches

  • Thein, Wynn;Po, Wah Wah;Choi, Won Seok;Sohn, Uy Dong
    • Biomolecules & Therapeutics
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    • v.29 no.4
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    • pp.353-364
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    • 2021
  • The gastrointestinal (GI) tract is a series of hollow organs that is responsible for the digestion and absorption of ingested foods and the excretion of waste. Any changes in the GI tract can lead to GI disorders. GI disorders are highly prevalent in the population and account for substantial morbidity, mortality, and healthcare utilization. GI disorders can be functional, or organic with structural changes. Functional GI disorders include functional dyspepsia and irritable bowel syndrome. Organic GI disorders include inflammation of the GI tract due to chronic infection, drugs, trauma, and other causes. Recent studies have highlighted a new explanatory mechanism for GI disorders. It has been suggested that autophagy, an intracellular homeostatic mechanism, also plays an important role in the pathogenesis of GI disorders. Autophagy has three primary forms: macroautophagy, microautophagy, and chaperone-mediated autophagy. It may affect intestinal homeostasis, host defense against intestinal pathogens, regulation of the gut microbiota, and innate and adaptive immunity. Drugs targeting autophagy could, therefore, have therapeutic potential for treating GI disorders. In this review, we provide an overview of current understanding regarding the evidence for autophagy in GI diseases and updates on potential treatments, including drugs and complementary and alternative medicines.

Functional outcomes in children with reduction glossectomy for vascular malformations - "less is more!"

  • Thomas, John K.;Gaikwad, Vivek Samuel;Babu, Telugu Ramesh;Mathai, John;Srinivas, Rohit;Karl, Immanuel Sampath
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.47 no.3
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    • pp.209-215
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    • 2021
  • Objectives: Vascular malformation (VM) of the tongue can cause true macroglossia in children. Reduction glossectomy provides primary relief when sclerotherapy has failed or is not possible. In this study, we evaluated the surgical role in functional outcome of reduction glossectomy performed for VM of the tongue. Patients and Methods: We evaluated the functional and surgical outcomes of seven children who were treated at a tertiary care centre in Southern India between 2013 and 2018. Results: Six children underwent median glossectomy, while one child underwent lateral glossectomy. Functional assessment was performed at least 2 years after the date of surgery. At the time of assessment, speech was comprehensible for three children and was occasionally unintelligible in four children. Taste and swallowing were normal in all seven children. Six children exhibited a minimal residual lesion after surgery, of which only one was symptomatic. Residual lesions were managed with sclerotherapy (n=3), observation (n=2), or repeat surgery (n=1). Conclusion: Reduction glossectomy in children with macroglossia secondary to VMs has acceptable outcomes in terms of cosmesis and speech, with no gastronomic restriction.

Virtual screening, molecular docking studies and DFT calculations on JNK3

  • Priya, dharshini;Thirumurthy, Madhavan
    • Journal of Integrative Natural Science
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    • v.15 no.4
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    • pp.179-186
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    • 2022
  • The c-Jun N-terminal kinase (JNK3) play major role in neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, cerebral ischemia and other Central Nervous System disorders. Since JNK3 is primarily stated in the brain and stimulated by stress-stimuli, this situation is conceivable that inhibiting JNK3 could be a possible treatment for the mechanisms underlying neurodegenerative diseases. In this study drugs from Zinc15 database were screened to identify the JNK3 inhibitors by Molecular docking and Density functional theory approach. Molecular docking was done by Autodock vina and the ligands were selected based on the binding affinity. Our results identified top ten novel ligands as potential inhibitors against JNK3. Molecular docking revealed that Venetoclax, Fosaprepitant and Avapritinib exhibited better binding affinity and interacting with proposed binding site residues of JNK3. Density functional theory was used to compute the values for energy gap, lowest unoccupied molecular orbital (LUMO), and highest occupied molecular orbital (HOMO). The results of Density functional theory study showed that Venetoclax, Fosaprepitant and Avapritinib serves as a lead compound for the development of JNK3 small molecule inhibitors.

Functional Haplotypes and Evolutionary Analyses of SBE1 in Collected Rice Germplasm

  • Thant Zin Maung;Yong-Jin Park
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.216-216
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    • 2022
  • The starch-branching enzymes (BEs) are responsible for synthesizing the amylopectin, which plays an important role in determining the structural and physical properties of starch granules. BE has two differently functioning isoforms (BEI and BEIIa/b) based on their difference in the chain-length pattern by the degree of polymerization (DP), which mainly contributes to the amylopectin chain length distribution in starch biosynthesis. In this study, we investigated functional haplotypes and evolutionary analyses of SBE1 in 374 rice accessions (320 Korean bred and 54 wild). The analyses were performed based on the classified subpopulations. Haplotype analysis generates a total of 8 haplotypes, of which only four haplotypes were functional carrying four functional SNPs in four different exons of SBE1 on chromosome 6. Nucleotide diversity analysis showed a highest pi-value in aromatic group (0.0029), while the lowest diversity value was in temperate japonica (0.0002), indicating the signal of this gene evolution origin. Different directional selections could be estimated by negative Tajima's D value of temperate japonica (-1.1285) and positive Tajima's D value of tropical japonica (0.9456), where the selective sweeps were undergone by both positive purifying and balancing selections. Phylogenetic analysis indicates a closer relationship of the wild with most of the cultivated subgroups indicating a common ancestor for SBE1 gene. FST-values indicate distant genetic relationships of temperate japonica from all other classified groups. PCA and population structure analysis show an admixed structure of wild and cultivated subpopulations in some proportions.

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