• Animal cells and systems
• /
• 제8권3호
• /
• pp.205-212
• /
• 2004

The tumor suppressor protein p53 is stabilized by the herpes-virus-associated ubiquitin-specific protease (HAUSP), a deubiquitinating enzyme. We previously isolated and characterized a mouse orthologue of HAUSP, mHAUSP. mHAUSP cDNA consisted of 3,312 bp encodes 1,103 amino acids with a molecular weight of approximately 135 kDa containing highly conserved Cys, Asp (I), His, and Asn/Asp (II) domains. In this study, we carried out site-directed mutagenesis of 6 conserved amino acids (Cys224, Gln231, Asp296, His457, His465, and Asp482) in Cys box, QQD box, and His box. Interestingly, the conserved Gln 231 was not essential for the catalytic activity of mHAUSP. However, the other conserved amino acids were required for deubiquitinating activity of mHAUSP. We performed isopeptidase assay and confirmed that mHAUSP is able to remove ubiquitin from ubiquitinated substrates. In addition, we observed that mHAUSP induces apoptosis in HeLa cells.

• Molecules and Cells
• /
• 제43권3호
• /
• pp.203-214
• /
• 2020

Post-translational modifications play major roles in the stability, function, and localization of target proteins involved in the nervous system. The ubiquitin-proteasome pathway uses small ubiquitin molecules to degrade neuronal proteins. Deubiquitinating enzymes (DUBs) reverse this degradation and thereby control neuronal cell fate, synaptic plasticity, axonal growth, and proper function of the nervous system. Moreover, mutations or downregulation of certain DUBs have been found in several neurodegenerative diseases, as well as gliomas and neuroblastomas. Based on emerging findings, DUBs represent an important target for therapeutic intervention in various neurological disorders. Here, we summarize advances in our understanding of the roles of DUBs related to neurobiology.

• 대한생식의학회:학술대회논문집
• /
• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
• /
• pp.150.2-150.2
• /
• 2006

• Molecules and Cells
• /
• 제41권11호
• /
• pp.933-942
• /
• 2018

Traditionally, small-molecule or antibody-based therapies against human diseases have been designed to inhibit the enzymatic activity or compete for the ligand binding sites of pathological target proteins. Despite its demonstrated effectiveness, such as in cancer treatment, this approach is often limited by recurring drug resistance. More importantly, not all molecular targets are enzymes or receptors with druggable 'hot spots' that can be directly occupied by active site-directed inhibitors. Recently, a promising new paradigm has been created, in which small-molecule chemicals harness the naturally occurring protein quality control machinery of the ubiquitin-proteasome system to specifically eradicate disease-causing proteins in cells. Such 'chemically induced protein degradation' may provide unprecedented opportunities for targeting proteins that are inherently undruggable, such as structural scaffolds and other non-enzymatic molecules, for therapeutic purposes. This review focuses on surveying recent progress in developing E3-guided proteolysis-targeting chimeras (PROTACs) and small-molecule chemical modulators of deubiquitinating enzymes upstream of or on the proteasome.

• BMB Reports
• /
• 제51권6호
• /
• pp.261-262
• /
• 2018

Aurora B is an important kinase involved in dynamic cellular events in mitosis. Aurora B activity is controlled by several post-translational modifications (PTMs). Among them, E3 ubiquitin ligase-mediated ubiquitination plays crucial roles in controlling the relocation and degradation of Aurora B. Aurora B, ubiquitinated by different E3 ligases, moves to the exact site for its mitotic function during metaphase-anaphase transition and is then degraded for cell cycle progression at the end of mitosis. However, how the stability of Aurora B is maintained until its degradation has been poorly understood. Recently, we have found that USP35 acts as a deubiquitinating enzyme (DUB) for Aurora B and affects its stability during cell division, thus being involved in the regulation of mitosis. In this review, we discuss the USP35-mediated deubiquitination of Aurora B and the regulation of mitotic progression by USP35.

• 대한생식의학회:학술대회논문집
• /
• 대한불임학회 2005년도 제48차 춘계 학술대회
• /
• pp.122.2-123
• /
• 2005

• 생명과학회지
• /
• 제20권7호
• /
• pp.1005-1011
• /
• 2010

$\gamma$-aminobutyric acid (GABA)는 중추신경계에서 억제성으로 작용하는 주요한 신경전달물질이다. GABA 수송체(GAT)는 연접간격에 존재하는 GABA를 세포 내로 재 흡수하여 GABA의 농도를 조절한다. 그런데 GABA 수송체가 어떻게 조절되는지는 아직 밝혀지지 않았다. 본 연구에서는 효모 two-hybrid system을 사용하여 뇌의 주요 GABA 수송체인 GAT1의 C-말단과 특이적으로 결합하는 ubiquitin-specific protease 14 (Usp14)를 분리하였다. Usp14는 GABA 수송체 GAT1및 GAT2와는 결합하지만, 다른 GAT isoform과는 결합하지 않았다. GAT1과의 결합에는 Usp14의 C-말단부위가 필수적으로 관여함을 확인하였다. 또한 이 단백질간의 결합을 GST pull-down assay로 확인하였으며, 생쥐 뇌 균질액의 co-immunoprecipitation을 통하여 in vivo에서도 GAT1과 Usp14가 결합함을 확인하였다. 이러한 결과들은 Usp14가 GAT1과 결합하여 세포막에 존재하는 GAT1의 수를 조절하는 역할을 할 가능성을 시사한다.

• 미생물학회지
• /
• 제52권2호
• /
• pp.236-241
• /
• 2016

탈유비퀴틴 효소 중 PPPDE 상과에 속하는 Schizosaccharomyces pombe의 $sdu1^+$ 유전자가 유비퀴틴 C-말단 가수분해 효소 활성을 갖는 단백질을 인코딩하고, 산화적 및 일산화질소 스트레스 방어에 관여함이 이전에 밝혀진 바 있다. 예비적인 본 연구는 정상적인 및 과잉발현의 조건에서 S. pombe 유비퀴틴 C-말단 가수분해 효소 활성의 활성산소종 의존성 조절에 초점을 맞추었다. 과산화수소, 수퍼옥사이드 라디칼 생성하는 메나디온 및 일산화질소 생성하는 sodium nitroprusside (SNP)에 노출시킨 S. pombe 세포에서 유비퀴틴 C-말단 가수분해 효소 활성이 감소되었다. 환원형 글루타치온과 그 전구체인 N-acetylcysteine은 과산화수소의 존재 유무에 상관없이 유비퀴틴 C-말단 가수분해 효소 활성을 현저하게 증강시켰다. 그러나, 과산화수소의 부재 시 혹은 존재 시 활성산소종에 미치는 글루타치온과 N-acetylcysteine의 영향은 같은 조건 하에서의 유비퀴틴 C-말단 가수분해 효소 활성 패턴과 상반되었다. 과잉발현의 유비퀴틴 C-말단 가수분해 효소 활성을 보이는 재조합 플라즈미드 pYSTP를 보유하는 S. pombe 세포에서 유비퀴틴 C-말단 가수분해 효소 활성도 과산화수소, 메나디온 및 SNP에의 노출되는 조건에서 감소되었지만, 벡터 대조 세포에서 보다는 높게 유지되었다. 요약하면, S. pombe 유비퀴틴 C-말단 가수분해 효소 활성은 활성산소종에 의하여 하향조절 되지만, 그 의의는 현재로썬 알려지고 있지 않은 상태이다.

• BMB Reports
• /
• 제47권7호
• /
• pp.411-416
• /
• 2014

In the present study, we demonstrate that ectopic expression of 56-kDa human selenium binding protein-1 (hSP56) in PC-3 cells that do not normally express hSP56 results in a marked inhibition of cell growth in vitro and in vivo. Down-regulation of hSP56 in LNCaP cells that normally express hSP56 results in enhanced anchorage-independent growth. PC-3 cells expressing hSP56 exhibit a significant reduction of hypoxia inducible protein (HIF)-$1{\alpha}$ protein levels under hypoxic conditions without altering HIF-$1{\alpha}$ mRNA (HIF1A) levels. Taken together, our findings strongly suggest that hSP56 plays a critical role in prostate cells by mechanisms including negative regulation of HIF-$1{\alpha}$, thus identifying hSP56 as a candidate anti-oncogene product.

• BMB Reports
• /
• 제56권8호
• /
• pp.451-456
• /
• 2023

Deubiquitinases (DUBs) are an essential component of the ubiquitin-proteasome system (UPS). They trim ubiquitin from substrate proteins, thereby preventing them from degradation, and modulate different cellular processes. Ubiquitin-specific protease 14 (USP14) is a DUB that has mainly been studied for its role in tumorigenesis in several cancers. In the present study, we found that the protein levels of USP14 were remarkably higher in gastric cancer tissues than in the adjacent normal tissues. We also demonstrated that the inhibition of USP14 activity using IU1 (an USP14 inhibitor) or the inhibition of USP14 expression using USP14-specific siRNA markedly reduced the viability of gastric cancer cells and suppressed their migratory and invasive abilities. The reduction in gastric cancer cell proliferation due to the inhibition of USP14 activity was a result of the increase in the degree of apoptosis, as evidenced by the increased expression levels of cleaved caspase-3 and cleaved PARP. Furthermore, an experiment using the USP14 inhibitor IU1 revealed that the inhibition of USP14 activity suppressed 5-fluorouracil (5-FU) resistance in GC cells. Collectively, these findings indicate that USP14 plays critical roles in gastric cancer progression and suggest its potential to serve as a novel therapeutic target for gastric cancer treatment.