• Molecules and Cells
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• 제20권2호
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• pp.167-172
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• 2005

Ceruloplasmin (Cp) is a copper protein with important functions in iron homeostasis and in inflammation. Cp mRNA expression is induced by interferon (IFN)-${\gamma}$ in U937 monocytic cells, but synthesis of Cp protein is halted after about 12 h by transcript-specific translational silencing. The silencing mechanism requires binding of a 4-component cytosolic inhibitor complex, IFN-gamma-activated inhibitor of translation (GAIT), to a defined structural element (GAIT element) in the Cp 3'-UTR. Translational silencing of Cp mRNA requires the essential proteins of mRNA circularization, suggesting that the translational inhibition requires end-to-end mRNA closure. These studies describe a new mechanism of translational control, and may shed light on the role that macrophage-derived Cp plays at the intersection of iron homeostasis and inflammation.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.236-238
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• 2009

• Journal of Plant Biotechnology
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• 제38권1호
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• pp.87-93
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• 2011

SAMDC는 폴리아민 생합성 과정에서 주효소로 작용하며 항상성을 유지하기위해 정교하게 조절된다. 카네이션 SAMDC 유전자는 5'-leader sequence에 54개 아미노산으로 구성된 small uORF가 존재한다. Translation 과정을 조절하는 uORF의 작용기작을 연구하기 위하여 35S 프로모터에 SAMDC 유전자의 uORF 부위와 GUS 유전자를 재조합한 형질전환 담배 식물체를 이용하였다. 본 실험에서는 SAMDC uORF 염기서열 혹은 SAMDC uORF 단백질에 의해서 downstream GUS ORF의 translation이 억제되었다. 특히 translation 억제는 개시코돈이 point-mutation된 construct에서 효과적으로 이루어졌다. 따라서 이러한 결과는 ribosomal stalling이 translation 억제 과정에 관여한 것으로 사료된다. 개시 코돈과 종결코돈을 가진 SAMDC uORF의 아미노산 서열을 frame shift 시키면 GUS 활성이 증가하였는데 이는 translation inhibitor로서 작용할 때 아미노산 서열이 중요하다는 것을 의미하며, 결국은 SAMDC uORF의 단백질 구조가 중요하게 작용할 가능성을 제시한다. 또한 유식물과 담배 꽃 등의 in vivo 상에서도 GUS 발현을 조직화학적으로 분석했을 때 small uORF가 존재할 경우 GUS 염색이 크게 저하되었지만, 개시코돈이나 혹은 종결코돈이 제거되도록 point-mutation 시킨 construct가 도입된 형질전환식물체에서는 SAMDC uORF의 억제효과가 크게 완화 되었다. 또한 가장 중요한 관찰 결과로는 small uORF 염기서열로부터 in vitro 시스템에서 5.7 kDa의 단백질이 실제적으로 합성되었음을 관찰하였다. 폴리아민 처리 후 GUS 단백질이 억제된 결과는 uORF로부터 합성된 단백질이 폴리아민 뿐 만 아니라 translation 과정에 관여하는 다른 요소들과 상호작용을 이루어 조절될 수 있음을 암시한다.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.924-926
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• 2009

• The Korean Journal of Physiology and Pharmacology
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• 제27권4호
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• pp.399-406
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• 2023

Voltage-dependent K⁺ (Kv) channels are widely expressed on vascular smooth muscle cells and regulate vascular tone. Here, we explored the inhibitory effect of encainide, a class Ic anti-arrhythmic agent, on Kv channels of vascular smooth muscle from rabbit coronary arteries. Encainide inhibited Kv channels in a concentration-dependent manner with an IC₅₀ value of 8.91 ± 1.75 μM and Hill coefficient of 0.72 ± 0.06. The application of encainide shifted the activation curve toward a more positive potential without modifying the inactivation curve, suggesting that encainide inhibited Kv channels by altering the gating property of channel activation. The inhibition by encainide was not significantly affected by train pulses (1 and 2 Hz), indicating that the inhibition is not use (state)-dependent. The inhibitory effect of encainide was reduced by pretreatment with the Kv1.5 subtype inhibitor. However, pretreatment with the Kv2.1 subtype inhibitor did not alter the inhibitory effects of encainide on Kv currents. Based on these results, encainide inhibits vascular Kv channels in a concentration-dependent and use (state)-independent manner by altering the voltage sensor of the channels. Furthermore, Kv1.5 is the main Kv subtype involved in the effect of encainide.

• Molecules and Cells
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• 제25권1호
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• pp.86-90
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• 2008

Caspase-3 (CASP3) plays a key role in apoptosis. In this study, HAX-1 was identified as a new substrate of CASP3 during apoptosis. HAX-1 was cleaved by CASP3 during etoposide-(ETO) induced apoptosis, and this event was inhibited by a CASP3-specific inhibitor. The cleavage site of HAX-1, at $Asp^{127}$, was located using N-terminal amino acid sequencing of in vitro cleavage products of recombinant HAX-1. Overexpression of HAX-1 inhibited ETO-induced apoptotic cell death. It also inhibited CASP3 activity. Together, these results suggest that HAX-1, a substrate of CASP3, inhibits the apoptotic process by inhibiting CASP3 activity.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.2985-2989
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• 2014

Autophagy is a self-digestion process in which intracellular structures are degraded in response to stress. Notably, prolonged autophagy leads to cell death. In this study, we investigated whether CX-4945, an orally available protein kinase 2 (CK2) inhibitor, induces autophagic cell death in human cervical cancer-derived HeLa cells and in human prostate cancer-derived LNCaP cells. CX-4945 treatment of both cell lines resulted in the formation of autophagosomes, in the conversion of microtubule-associated protein 1 light chain 3 (LC3), and in down-regulation of the Akt-mammalian target of rapamycin (mTOR)-p70 ribosomal protein S6 kinase (S6K) signaling cascade. Thus, pharmacologic inhibition of CK2 by CX-4945 induced autophagic cell death in human cancer cells by down-regulating Akt-mTOR-S6K. These results suggest that autophagy-inducing agents have potential as anti-cancer drugs.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.2063-2066
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• 2012

• 한국식물학회:학술대회논문집
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• 한국식물학회 2002년도 춘계학술발표대회:발표눈문요지록
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• pp.100-100
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• 2002

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.477-485
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• 2016

CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats.