• Title/Summary/Keyword: subunits$(\alpha'-,\

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Stage and Tissue Specific Expression of Four TCR Subunits in Olive Flounder (Paralichthys olivaceus)

  • Lee, Young Mee;Lee, Jeong-Ho;Noh, Jae Koo;Kim, Hyun Chul;Park, Choul-Ji;Park, Jong-Won;Hwang, In Joon;Kim, Sung Yeon
    • Development and Reproduction
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    • v.17 no.4
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    • pp.329-335
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    • 2013
  • TCR subunits are members of membrane-bound receptors which allow the fast and efficient elimination of the specific fish pathogens have regulated function in adaptive immunity. Sequence structure of TCR subunits have been reported for various teleosts, but the information of each TCR subunit functional characterization through expression analysis in fish was unknown. In this study, we examined the gene expression of TCR subunits in the early developmental stages and observed transcript levels in various tissues from healthy adult olive flounder by RT-PCR. The mRNA expression of alpha subunit was already detected in the previous hatching step. But the transcripts of another TCR subunit were not observed during embryo development and increased after hatching and maintained until metamorphosis at the same level. It was found that all TCR subunits mRNAs are commonly expressed in the immune-related organ such as spleen, kidney and gill, also weak expressed in fin and eye. TCR alpha and beta subunit were expressed in brain, whereas gamma and delta were not expressed same tissue. The sequence alignment analysis shows that there are more than 80% sequence homology between TCR subunits. Because it has a high similarity of amino acid sequence to expect similar in function, but expression analysis show that will have may functional diversity due to different time and place of expression.

Isolation of cDNAs for Gonadotropin-II of Flounder (Paralichthys olivaceus) and Its Expressions in Adult Tissues

  • Lee, Jae-Hyung;Nam, Soo-Wan;Kim, Young-Tae
    • Journal of Microbiology and Biotechnology
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    • v.13 no.5
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    • pp.710-716
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    • 2003
  • Gonadotropin (GTH) is a pituitary glycoprotein hormone that regulates gonadal development in vertebrates. In teleosts, two types of gonadotropins, GTH-I and GTH-II, are produced in the pituitary, and they comprised of common ${\alpha}$ and distinct ${\beta}$ subunits. In the present study, the cDNAs encoding GTH ${\alpha}\;and\;GTH-II{\beta}$ subunits were cloned and sequenced from flounder (Paralichthys olivaceus) pituitary cDNA library. The nucleotide sequence of the a subunit was 619 bp long, encoding 124 amino acids, and that of the $GTH-II{\beta}$ subunit was 538 bp long, encoding 145 amino acids. GTH subunits had well conserved cysteines, when aligned with other members of the glycoprotein family. The ${\beta}$ subunit of gonadotropin II ($GTH-II{\beta}$) had a different N-linked glycosylation site. RT-PCR analysis showed an increase of GTH II mRNA levels in association with gonadal development, and also showed that the mRNA expression of the ${\alpha}$ subunit was detected only in tissues from pituitary glands.

G$\alpha$12 and G$\alpha$13 Subunits Modulate $Ca^{2+}$-Induced Histamine Release in Human Umbilical Cord Blood-Derived Mast Cells

  • Ro, Jai-Youl;Kim, Ji-Young;Ha, Ji-Hee;Lee, Chang-Ho
    • Journal of Microbiology and Biotechnology
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    • v.12 no.3
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    • pp.483-489
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    • 2002
  • The role of $G{\alpha}12\;and\;G{\alpha}13$ in modulating the IgE receptor-mediated histamine secretion in the streptolysin-o-permeabilized human cultured mast cell was investigated. The expression of $G{\alpha}12\;and\;G{\alpha}13$ proteins were regulated during human cultured mast cell differentiation, and a significant correlation was observed between the levels of expression of $G{\alpha}12\;and\;G{\alpha}13$ proteins and IgE receptor-mediated histamine secretion capability in human cultured mast cells. Antibodies against $G{\alpha}12\;and\;G{\alpha}13$ effectively inhibited the IgE receptor-induced histamine release, and the concentration of anti-$G{\alpha}12$ antibody used to inhibit histamine secretion was shown to also inhibit the IgE receptor-mediated elevation of intracellular $Ca^2+$. Therefore, the results suggest that $G{\alpha}12\;and\;G{\alpha}13$ play roles in modulating IgE receptor-activated $Ca^2+$ influx, thereby regulating histamine release in cultured human mast cells. This is the first report to show that $G{\alpha}12\;and\;G{\alpha}13$ are involved in the regulation of $Ca^2+$ mediated exocytosis in human cultured mast cells.

In Vitro Characterization of Protein Kinase CKII β Mutants Defective in β-β Dimerization

  • Kim, Tae-Hyun;Lee, Jae-Yong;Kang, Beom Sik;Bae, Young-Seuk
    • Molecules and Cells
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    • v.19 no.1
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    • pp.124-130
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    • 2005
  • Protein kinase CKII is composed of two catalytic (${\alpha}$ or ${\alpha}^{\prime}$) subunits and two regulatory (${\beta}$) subunits. The ${\beta}$ subunit mediates tetramer formation through ${\beta}-{\beta}$ homodimerization and ${\alpha}-{\beta}$ heterodimerization. In a previous study R26 and R75, point mutants of $CKII{\beta}$ defective in ${\beta}-{\beta}$ dimerization, were isolated. In the present work we characterized these $CKII{\beta}$ mutants in vitro. Purified R26 and R75 bound to $CKII{\alpha}$ but were defective in binding to $CKII{\beta}$. R75 stimulated the catalytic activity of CKII whereas R26 gave little stimulation, and poly-L-lysine increased the stimulation of catalytic activity by R26 or R75. Circular dichroism and intrinsic fluorescence data pointed to different conformational changes in R26 and R75. Molecular modeling of these mutants provides an explanation of the difference in their ability to interact with $CKII{\beta}$ and to activate $CKII{\alpha}$.

Differential Coupling of G$\alpha$q Family of G-protein to Muscarinic $M_1$ Receptor and Neurokinin-2-Receptor

  • Lee, Chang-Ho;Shin, In-Chul;Kang, Ju-Seop;Koh, Hyun-Chul;Ha, Ji-Hee;Min, Chul-Ki
    • Archives of Pharmacal Research
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    • v.21 no.4
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    • pp.423-428
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    • 1998
  • The ligand binding signals to a wide variety of seven transmembrane cell surface receptors are transduced into intracellular signals through heterotrimeric G-proteins. Recently, there have been reports which show diverse coupling patterns of ligand-activated receptors to the members of Gq family $\alpha$ subunits. In order to shed some light on these complex signal processing networks, interactions between G$\alpha$q family of G protein and neurokinin-2 receptor as well as muscarinic M$_{1}$ receptor, which are considered to be new thearpeutic targets in asthma, were studied. Using washed membranes from Cos-7 cells co-transfected with different G.alpha.q and receptor cDNAs, the receptors were stimulated with various concentrations of carbachol and neurokinin A and the agonist-dependent release of [$^3H$]inositol phosphates through phospholipase C beta-1 activation was measured. Differential coupling of Gaq family of G-protein to muscarinic M$_{1}$ receptor and neurokinin-2 receptor was observed. The neurokinin-2 receptor shows a ligand-mediated response in membranes co-transfected with G$\alpha$q, G$\alpha$11 and G$\alpha$14 but not G$\alpha$16 and the ability of the muscarinic $M_1$ receptor to activate phospholipase C through G$\alpha$/11 but not G$\alpha$14 and G$\alpha$16 was demonstrated. Clearly G$\alpha$/11 can couple $\M_1$ and neurokinin-2 receptor to activate phospholipase C. But, there are differences in the relative coupling of the G$\alpha$14 and G$\alpha$16 subunits to these receptors.

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Cell Behavior of Human Papillomavirus-immortalized and Tumorigenic Human Oral Keratinocytes Does Not Depend on the Integrin Expression

  • Park, Kyung-Hee;Min, Byung-Moo
    • International Journal of Oral Biology
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    • v.32 no.3
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    • pp.93-101
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    • 2007
  • Cell behavior of the transformed cells is known to affect by interaction with extracellular matrix (ECM) proteins and integrin. To investigate the alterations of both integrin expression and cell-matrix interaction during neoplastic conversion of human oral kerationcytes, we studied expression levels of integrin subunits by flow cytometry and cellular responses to the ECM proteins in normal human oral keratinocytes (NHOKs), HPV-immortalized HOK-16B line, and three oral cancer cell lines established from HOK-16B line, CTHOK-16B-BaP, CTHOK-16B-DMBA, and CTHOK-16B-Dexa lines. The expression levels of ${\alpha}\;and\;{\beta}$ integrin subunits were shown decreased tendency in human oral keratinocytes undergoing immortalization and tumorigenic transformation except CTHOK-16B-DMBA line tested. Although ${\alpha}v{\beta}6$ integrin is known to be highly expressed in squamous cell carcinomas, and the altered integrin expression is suspected to be associated with cellular carcinogenesis, ${\alpha}v$ integrin subunit and ${\alpha}v{\beta}6$ integrin did not express in oral cancer cell lines tested. Cell behavior to the ECM proteins in HOK-16B line was generally similar to that of exponentially proliferating NHOKs. The adhesion activity profiles of type I collagen were very similar to that of its laminin counterparts, but fibronectin showed minimal adhesion activity under our conditions compared to the BSA control. The ability of the CTHOK-16B-BaP line to spread upon type I collagen and laminin markedly decreased, but migration was notably increased on type I collagen. In contrast, CTHOK-16B-DMBA and CTHOK-16B-Dexa lines spread less but migrated more upon type I collagen than immortalized HOK-16B line. These data indicate that downregulation of integrin subunits causes the changes of cellular responses to the ECM proteins during neoplastic conversion of human oral keratinocytes, and that cellular responses to the ECM proteins in oral cancer cell lines established by exposing different carcinogens are variable according to chemical carcinogens treatment.

Molecular Dissection of the Interaction between hBLT2 and the G Protein Alpha Subunits

  • Vukoti, Krishna Moorthy;Lee, Won-Kyu;Kim, Ho-Jun;Kim, Ick-Young;Yang, Eun-Gyeong;Lee, Cheol-Ju;Yu, Yeon-Gyu
    • Bulletin of the Korean Chemical Society
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    • v.28 no.6
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    • pp.1005-1009
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    • 2007
  • Leukotriene B4 (LTB4) is a potent chemoattractant for leukocytes and considered to be an inflammatory mediator. Human BLT2 (hBLT2) is a low-affinity G-protein coupled receptor for LTB4 and mediates pertussis toxin-sensitive chemotactic cell movement. Here, we dissected the interaction between hBLT2 and G-protein alpha subunits using GST fusion proteins containing intracellular regions of hBLT2 and various Gα protein including Gα i1, Gα i2, Gα i3, Gα s1, Gα o1, and Gα z. Among the tested Gα subunits, Gα i3 showed the highest binding to the third intracellular loop region of hBLT2 with a dissociation constant (KD) of 5.0 × 10?6 M. These results suggest that Gα i3 has the highest affinity to hBLT2, and the third intracellular loop region of hBLT2 is the major component for the interaction with Gα i3.

The Integrins Involved in Soybean Agglutinin-Induced Cell Cycle Alterations in IPEC-J2

  • Pan, Li;Zhao, Yuan;Yuan, Zhijie;Farouk, Mohammed Hamdy;Zhang, Shiyao;Bao, Nan;Qin, Guixin
    • Molecules and Cells
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    • v.40 no.2
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    • pp.109-116
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    • 2017
  • Soybean agglutinin (SBA) is an anti-nutritional factor of soybean, affecting cell proliferation and inducing cytotoxicity. Integrins are transmembrane receptors, mediating a variety of cell biological processes. This research aims to study the effects of SBA on cell proliferation and cell cycle progression of the intestinal epithelial cell line from piglets (IPEC-J2), to identify the integrin subunits especially expressed in IPEC-J2s, and to analyze the functions of these integrins on IPEC-J2 cell cycle progression and SBA-induced IPEC-J2 cell cycle alteration. The results showed that SBA lowered cell proliferation rate as the cell cycle progression from G0/G1 to S phase (P < 0.05) was inhibited. Moreover, SBA lowered mRNA expression of cell cycle-related gene CDK4, Cyclin E and Cyclin D1 (P < 0.05). We successfully identified integrins ${\alpha}2$, ${\alpha}3$, ${\alpha}6$, ${\beta}1$, and ${\beta}4$ in IPEC-J2s. These five subunits were crucial to maintain normal cell proliferation and cell cycle progression in IPEC-J2s. Restrain of either these five subunits by their inhibitors, lowered cell proliferation rate, and arrested the cells at G0/G1 phase of cell cycle (P < 0.05). Further analysis indicated that integrin ${\alpha}2$, ${\alpha}6$, and ${\beta}1$ were involved in the blocking of G0/G1 phase induced by SBA. In conclusion, these results suggested that SBA lowered the IPEC-J2 cell proliferation rate through the perturbation of cell cycle progression. Furthermore, integrins were important for IPEC-J2 cell cycle progression, and they were involved in the process of SBA-induced cell cycle progression alteration, which provide a basis for further revealing SBA anti-proliferation and anti-nutritional mechanism.

Effects of Temperature and Urea on in vitro Aggregation of Tryptophan Synthase $\alpha$-Subunits

  • Park, Myung-Won;Jeong, Jae-Kap;Shin, Hae-Ja;Lim, Woon-Ki
    • Biomedical Science Letters
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    • v.9 no.4
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    • pp.203-207
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    • 2003
  • Protein aggregation could be problematic as causes of diseases and hindrance in the production of useful recombinant proteins. Aggregation of mutant tryptophan synthase $\alpha$-subunits was examined by treatment with urea and at high temperature. Large amorphous aggregate seemed to appear by heat treatment, while more various aggregates in size were formed by treatment with urea at low concentration. The result indicates that different aggregate in size could be formed depending on the treatment condition, suggesting different mechanisms underlying aggregation processes.

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Functional Effects of $\beta4$-Subunit on Rat $BK_{Ca}$ Channel $\alpha$-Subunit, rSlo

  • Ha, Tal-Soo;Heo, Moon-Sun;Park, Chul-Seung
    • Proceedings of the Korean Biophysical Society Conference
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    • 2002.06b
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    • pp.32-32
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    • 2002
  • To understand the functional roles of the neuron-specific $\beta$-subunit of large-conductance calcium-activated potassium ($BK_{Ca}$) channel, we isolate the full-length complementary DNA of $\beta$4-subunit from rat brain library and investigated its effects on the function of $\alpha$-subunit (Slo). The deduced amino acid sequence of rat $\beta$4 (r$\beta$4), 210 amino acids in length, was closely related to those of $\beta$4 subunits in other mammalian species but showed only a limited sequence homology to the other $\beta$-subunits, $\beta$1 to $\beta$3.(omitted)d)

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