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Dong-Uk Kim,
Jacqueline Hayles,
Dongsup Kim,
Valerie Wood,
Han-Oh Park,
Misun Won,
Hyang-Sook Yoo,
Trevor Duhig,
Miyoung Nam,
Georgia Palmer, [......],
Hae-Joon Park,
Eun-Jung Kang,
Hyong Bai Kim,
Hyun-Sam Kang,
Hee-Moon Park,
Kyunghoon Kim,
Kiwon Song,
Kyung Bin Song,
Paul Nurse,
Kwang-Lae Hoe
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ABSTRACT: We report the construction and analysis of 4,836 heterozygous diploid deletion mutants covering 98.4% of the fission yeast genome providing a tool for studying eukaryotic biology. Comprehensive gene dispensability comparisons with budding yeast--the only other eukaryote for which a comprehensive knockout library exists--revealed that 83% of single-copy orthologs in the two yeasts had conserved dispensability. Gene dispensability differed for certain pathways between the two yeasts, including mitochondrial translation and cell cycle checkpoint control. We show that fission yeast has more essential genes than budding yeast and that essential genes are more likely than nonessential genes to be present in a single copy, to be broadly conserved and to contain introns. Growth fitness analyses determined sets of haploinsufficient and haploproficient genes for fission yeast, and comparisons with budding yeast identified specific ribosomal proteins and RNA polymerase subunits, which may act more generally to regulate eukaryotic cell growth.
Nature Biotechnology 06/2010; 28(6):617-23. · 29.50 Impact Factor
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Kyung-Sun Heo,
Sung-Woo Ryoo,
Lila Kim,
Miyoung Nam, Seung-Tae Baek,
Hyemi Lee,
Ah-Reum Lee,
Song-Kyu Park,
Youngwoo Park,
Chang-Seon Myung,
Dong-Uk Kim,
Kwang-Lae Hoe
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ABSTRACT: Low-density lipoprotein (LDL) induces cell proliferation in human aortic smooth muscle cells (hAoSMCs), which may be involved in atherogenesis and intimal hyperplasia. Recent studies have demonstrated that Cl- channels are related to vessel cell proliferation induced by a variety of stimuli. In this study, we investigated a potential role of Cl-channels in the signaling pathway of LDL effects on hAoSMC proliferation with a focus on the activation of Erk1/2-PI3K/Akt and the subsequent upregulation of Egr-1. Cl- channel blockers, DIDS, but neither NPPB nor Furosemide, completely abolished the LDL-induced DNA synthesis and cell proliferation. Moreover, DIDS, but not NPPB, significantly decreased LDL-stimulated Cl- concentration, as judged by flow cytometry analysis using MQAE as a Cl- -detection dye. DIDS pretreatment completely abolished the activation of Erk1/2 and PI3K/Akt in a dose-dependent manner that is the hallmark of LDL activation, as judged by Western blot and proliferation assays. Moreover, pretreatment with DIDS (Cl- channel blockers) but not LY294002 (PI3K inhibitors) completely abolished the LDL-induced upregulation of Egr-1 to the same extent as PD98059 (MEK inhibitors to inhibit Erk), as judged by Western blot and luciferase reporter assays. This is the first report, to our knowledge, that DIDS-sensitive Cl- channels play a key role in the LDL-induced cell proliferation of hAoSMCs via the activation of Erk1/2 and PI3K/Akt and the upregulation of Egr-1.
Molecules and Cells 09/2008; 26(5):468-73. · 2.18 Impact Factor
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Seung Tae Baek,
Sangjo Han,
Miyoung Nam,
Young-Dae Kim,
Lila Kim,
Hyun-Jee Lee,
Kyung-Sun Heo,
Hyemi Lee,
Minho Lee,
Song-Kyu Park,
Pil Jae Maeng,
Youngwoo Park,
Sunghou Lee,
Dong-Uk Kim,
Dongsup Kim,
Kwang-Lae Hoe
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ABSTRACT: Abnormal phenotypes resulting from haploinsufficiency (HI) are due to the loss of one allele. Recent studies in budding yeast have shown that HI originates from insufficient protein levels or from a stoichiometric imbalance between subunits of protein complexes. In humans, however, HI often involves transcription factors. Therefore, the species differences in HI and the molecular mechanisms of species-specific HI remain under investigation. In this study, HI in fission yeast was systematically surveyed. HI in fission yeast affected genes related to signaling and to basic cellular processes, as observed in budding yeast. These results suggest that there are species differences in HI and that the HI that occurs in fission yeast is intermediate to and HI in budding yeast and humans.
Journal of Microbiology and Biotechnology 07/2008; 18(6):1059-63. · 1.38 Impact Factor
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ABSTRACT: Native LDL may be a mitogenic stimulus of VSMC proliferation in lesions where endothelial disruption occurs. Recent studies have demonstrated that the mitogenic effects of LDL are accompanied by Erk1/2 activation via an unknown G-protein-coupled receptor (GPCR). In this article, we report that LDL translocated PKCbeta(II) and PKCtheta from cytosol to plasma membrane, and inhibition of PKCbeta(II) and PKCtheta decreased LDL effects via the deactivation of Erk1/2. Moreover, pertussis toxin, but not cholera toxin or heparin, inhibited LDL-induced translocation of PKCbeta(II) and PKCtheta, suggesting that Gi protein plays a role in LDL effects. Of LPA, S1P, and LDL, whose signaling is conveyed via Gi/o proteins, only LDL induced translocation of PKCbeta(II) and PKCtheta. Inhibition of PKCbeta(II) or PKCtheta, as well as of Erk1/2 and GPCR, decreases LDL-induced upregulation of Egr-1, which is critical for cell proliferation. This is the first report, to our knowledge, that the participation of PKCtheta in VSMC proliferation is unique.
Biochemical and Biophysical Research Communications 04/2008; 368(1):126-31. · 2.48 Impact Factor
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Seung Tae Baek,
Dong-Uk Kim,
Sangjo Han,
Im Sun Woo,
Miyoung Nam,
Lila Kim,
Kyung-Sun Heo,
Hyemi Lee,
Hye-Rim Hwang,
Shin-Jung Choi,
Misun Won,
Minho Lee,
Song-Kyu Park,
Sunghou Lee,
Ho-Jung Kwon,
Pil Jae Maeng,
Hee-Moon Park,
Youngwoo Park,
Dongsup Kim,
Kwang-Lae Hoe
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ABSTRACT: Hydrazinocurcumin (HC), a synthetic derivative of curcumin, has been reported to inhibit angiogenesis via unknown mechanisms. Understanding the molecular mechanisms of the drug's action is important for the development of improved compounds with better pharmacological properties. A genomewide drug-induced haploinsufficiency screening of fission yeast gene deletion mutants has been applied to identify drug targets of HC. As a first step, the 50% inhibition concentration (IC50) of HC was determined to be 2.2 microM. The initial screening of 4,158 mutants in 384-well plates using robotics was performed at concentrations of 2, 3, and 4 microM. A second screening was performed to detect sensitivity to HC on the plates. The first screening revealed 178 candidates, and the second screening resulted in 13 candidates, following the elimination of 165 false positives. Final filtering of the condition-dependent haploinsufficient genes gave eight target genes. Analysis of the specific targets of HC has shown that they are related to septum formation and the general transcription processes, which may be related to histone acetyl transferase. The target mutants showed 65% growth inhibition in response to HC compared with wild-type controls, as shown by liquid culture assay.
Journal of Microbiology and Biotechnology 03/2008; 18(2):263-9. · 1.38 Impact Factor
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ABSTRACT: Native LDL would be a mitogenic and chemotactic stimulus of VSMC proliferation and differentiation in the atherosclerotic lesion where endothelial disruption occurred. In previous studies, our group investigated the molecular mechanisms by which LDL induces IL-8 production and by which PPARalpha activation abolishes LDL effects in human aortic SMCs (hAoSMCs). Herein is the first report of PPARgamma activation by troglitazone (TG) exerting its inhibitory effects on LDL-induced cell proliferation via generation not of H(2)O(2), but of O2(.-), and the subsequent activation of Erk1/2 in hAoSMCs. Moreover, in this study TG abolished the LDL-accelerated G(1)-S progression to control levels via down-regulation of active cyclinD1/CDK4 and cyclinE/CDK2 complexes and up-regulation of p21(Cip1) expression. TG exerted its anti-proliferative effects through the up-regulation of basal superoxide dismutase (SOD) expression. This data suggests that the regulation of O2(.-) is located at the crossroads between LDL signaling and cell proliferation.
Biochemical and Biophysical Research Communications 09/2007; 359(4):1017-23. · 2.48 Impact Factor
