• Molecules and Cells
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• 제42권12호
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• pp.840-849
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• 2019

The spatiotemporal mitotic processes are controlled qualitatively by phosphorylation and qualitatively by ubiquitination. Although the SKP1-CUL1-F-box protein (SCF) complex and the anaphase-promoting complex/cyclosome (APC/C) mainly mediate ubiquitin-dependent proteolysis of mitotic regulators, the E3 ligase for a large portion of mitotic proteins has yet to be identified. Here, we report c-Cbl as an E3 ligase that degrades DDA3, a protein involved in spindle dynamics. Depletion of c-Cbl led to increased DDA3 protein levels, resulting in increased recruitment of Kif2a to the mitotic spindle, a concomitant reduction in spindle formation, and chromosome alignment defects. Furthermore, c-Cbl depletion induced centrosome over-duplication and centriole amplification. Therefore, we concluded that c-Cbl controls spindle dynamics and centriole duplication through its E3 ligase activity against DDA3.

• Journal of Plant Biotechnology
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• 제39권4호
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• pp.235-241
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• 2012

식물체에서 sumoylation 기작은 성장 및 발달에 중요한 기능을 수행할 것이다. 특히, SUMO E3 ligase는 SUMO 단백질을 목적 단백질로 전달해주는 마지막 단계의 sumoylation 기작 구성요소이며, 다양한 신호전달에 특이성을 나타내는 것으로 보고되고 있다. 본 연구에서는 벼에서 SUMO E3 ligase, SIZ1 유전자에 T-DNA가 삽입된 Ossiz1-2 돌연변이 식물체를 분석하였다. 그리고, OsSIZ1 단백질이 OsSUMO1 단백질과 상호작용함으로써 OsSIZ1이 SUMO E3 ligase의 기능을 수행할 것으로 예측하였다. Ossiz1-2 돌연변이 식물체는 형태학적으로 발달과 성장의 다양한 부분에서 미성숙상태로 유지됨이 보였다. 특히, 야생형인 동진벼와 비교하여 초장의 성장 및 등숙율에서 상당히 낮은 정도를 보여 주었다. 이와 같이, 벼에서 SUMO E3 ligase로써 OsSIZ1 단백질의 생리학적인 기능은 성장과 발달 그리고, 수확량에 관여하는 단백질을 sumoylation 시키는 기작에서 역할을 수행할 것으로 사려된다.

• Molecules and Cells
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• 제25권2호
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• pp.289-293
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• 2008

The role of SPOP in the ubiquitination of $ER{\alpha}$ by the Cullin3-based E3 ubiquitin ligase complex was investigated. We showed that the N-terminal region of SPOP containing the MATH domain interacts with the AF-2 domain of $ER{\alpha}$ in cultured human embryonic 293 cells. SPOP was required for coimmunoprecipitation of $ER{\alpha}$ with Cullin3. This is the first report of the essential role of SPOP in $ER{\alpha}$ ubiquitination by the Cullin3-based E3 ubiquitin ligase complex. We also demonstrated repression of the transactivation capability of $ER{\alpha}$ in cultured mammalian cells.

• BMB Reports
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• 제41권4호
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• pp.310-315
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• 2008

BirA ligase is a prokaryotic ortholog of holocarboxylase synthetase (HCS) that can biotinylate proteins. This study tested the hypothesis that BirA ligase catalyzes the biotinylation of eukaryotic histones. If so, this would mean that recombinant BirA ligase is a useful surrogate for HCS in studies of histone biotinylation. The biological activity of recombinant BirA ligase was confirmed by enzymatic biotinylation of p67. In particular, it was found that BirA ligase biotinylated both calf thymus histone H1 and human bulk histone extracts. Incubation of recombinant BirA ligase with H3-based synthetic peptides showed that lysines 4, 9, 18, and 23 in histone H3 are the targets for the biotinylation by BirA ligase. Modification of the peptides (e.g., serine phosphorylation) affected the subsequent biotinylation by BirA ligase, suggesting crosstalk between modifications. In conclusion, this study suggests that prokaryotic BirA ligase is a promiscuous enzyme and biotinylates eukaryotic histones. Moreover the biotinylation of histones by BirA ligase is consistent with the proposed role of human HCS in chromatin.

• Molecules and Cells
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• 제39권11호
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• pp.834-840
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• 2016

Caenorhabditis elegans (C. elegans) utilizes two different cell-cycle modes, binucleations during the L1 larval stage and endoreduplications at four larval moltings, for its postembryonic intestinal development. Previous genetic studies indicated that CDC-25.2 is specifically required for binucleations at the L1 larval stage and is repressed before endoreduplications. Furthermore, LIN-23, the C. elegans ${\beta}$-TrCP ortholog, appears to function as a repressor of CDC-25.2 to prevent excess intestinal divisions. We previously reported that intestinal hyperplasia in lin-23(e1883) mutants was effectively suppressed by the RNAi depletion of cdc-25.2. Nevertheless, LIN-23 targeting CDC-25.2 for ubiquitination as a component of E3 ubiquitin ligase has not yet been tested. In this study, LIN-23 is shown to be the major E3 ubiquitin ligase component, recognizing CDC-25.2 to repress their activities for proper transition of cell-cycle modes during the C. elegans postembryonic intestinal development. In addition, for the first time that LIN-23 physically interacts with both CDC-25.1 and CDC-25.2 and facilitates ubiquitination for timely regulation of their activities during the intestinal development.

• BMB Reports
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• 제55권5호
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• pp.232-237
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• 2022

The Wnt/β-catenin signaling plays crucial roles in early development, tissue homeostasis, stem cells, and cancers. Here, we show that RNF152, an E3 ligase localized to lysosomes, acts as a negative regulator of the Wnt/β-catenin pathway during Xenopus early embryogenesis. Overexpression of wild-type (WT) RNF152 inhibited XWnt8-induced stabilization of β-catenin, ectopic expression of target genes, and activity of a Wnt-responsive promoter. Likewise, an E3 ligase-defective RNF152 had repressive effects on the Wnt-dependent gene responses but not its truncation mutant lacking the transmembrane domain. Conversely, knockdown of RNF152 further enhanced the transcriptional responses induced by XWnt8. RNF152 morphants exhibited defects in craniofacial structures and pigmentation. In line with this, the gain-of-RNF152 function interfered with the expression of neural crest (NC) markers, whereas its depletion up-regulated NC formation in the early embryo. Mechanistically, RNF152 inhibits the polymerization of Dishevelled, which is key to Wnt signaling, in an E3 ligase-independent manner. Together, these results suggest that RNF152 controls negatively Wnt/β-catenin signaling to fine-tune its activity for NC formation in Xenopus embryo.

• 생명과학회지
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• 제28권10호
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• pp.1132-1139
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• 2018

진핵생물에서 유비퀴틴화 과정을 통해 단백질 안정성이 조절되며, E3 ligase는 유비퀴틴화 과정 동안 분해 대상 기질의 결정 및 기질로의 유비퀴틴 전달을 위한 주효소로 작용한다. Multi-subunit E3 ligase의 일종인 cullin4(CUL4)-based E3 ligase (CRL4) 복합체는 식물의 다양한 호르몬, 스트레스와 관련된 세포 내 과정에서 중요한 역할을 하는 것으로 알려져 있다. 호르몬, 스트레스 신호 전달 과정에서 CRL4의 다양한 역할에 대한 보고가 애기장대에서 이루어져 왔음에도 불구하고, 주요 식량 작물인 벼에서의 CRL4 기능에 대한 연구는 매우 미흡한 실정이다. 이에 벼에서 CRL4에 의해 매개되는 세포 내 반응들을 상세히 이해하기 위해, 본 연구에서는 애기장대 cullin4 (CUL4)의 상동 유전자를 벼에서 동정하고, 조직별 벼 CUL4 유전자의 발현 양상과 다양한 식물 호르몬 및 환경 스트레스 처리에 의한 해당 유전자의 발현 양상을 탐색하였다. 벼 CUL4 유전자인 OsCUL4는 앱시스산, 사이토키닌과 같은 식물 호르몬과 가뭄, 고염 스트레스에 의해 발현량이 급격히 상형 조절되는 양상을 보였는데 이는 해당 단백질이 앱시스산 및 사이토키닌에 의해 매개되는 세포 내 반응과 기능적으로 연계되어 있음을 암시한다. 또한, OsCUL4는 CRL4 복합체의 어댑터로 작용하는 OsDDB1과 직접적으로 결합하였는데, 이는 본 연구를 통해 동정한 OsCUL4가 벼에서 실질적으로 CRL4의 scaffold 단백질로 기능할 수 있음을 보여준다. 본 연구를 통해 수행된 OsCUL4 유전자의 발현 양상에 대한 연구는, 벼에서 CRL4 매개 유비퀴틴화 과정이 관여하는 세포 내 반응을 규명하기 위한 시작점으로 활용될 수 있을 것이라 사료된다.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2010년도 춘계 학술발표회 및 심포지엄
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• pp.134-135
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• 2010

• Mycobiology
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• 제39권4호
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• pp.243-248
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• 2011

The ubiquitin-proteasome system is one of the major protein turnover mechanisms that plays important roles in the regulation of a variety of cellular functions. It is composed of E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 ubiquitin ligases that transfer ubiquitin to the substrates that are subjected to degradation in the 26S proteasome. The Skp1, Cullin, F-box protein (SCF) E3 ligases are the largest E3 gene family, in which the F-box protein is the key component to determine substrate specificity. Although the SCF E3 ligase and its F-box proteins have been extensively studied in the model yeast Saccharomyces cerevisiae, only limited studies have been reported on the role of F-box proteins in other fungi. Recently, a number of studies revealed that F-box proteins are required for fungal pathogenicity. In this communication, we review the current understanding of F-box proteins in pathogenic fungi.

• BMB Reports
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• 제56권5호
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• pp.265-274
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• 2023

Defects in DNA double-strand break (DSB) repair signaling permit cancer cells to accumulate genomic alterations that confer their aggressive phenotype. Nevertheless, tumors depend on residual DNA repair abilities to survive the DNA damage induced by genotoxic stress. This is why only isolated DNA repair signaling is inactivated in cancer cells. DNA DSB repair signaling contributes to general mechanism for various types of lesions in diverse cell cycle phases. DNA DSB repair genes are frequently mutated and amplified in cancer; however, limited data exist regarding the overall genomic prospect and functional result of these modifications. We list the DNA repair genes and related E3 ligases. Mutation and expression frequencies of these genes were analyzed in COSMIC and TCGA. The 11 genes with a high frequency of mutation differed between cancers, and mutations in many DNA DSB repair E3 ligase genes were related to a higher total mutation burden. DNA DSB repair E3 ligase genes are involved in tumor suppressive or oncogenic functions, such as RNF168 and FBXW7, by assisting the functionality of these genomic alterations. DNA damage response-related E3 ligases, such as RNF168, FBXW7, and HERC2, were generated with more than 10% mutation in several cancer cells. This study provides a broad list of candidate genes as potential biomarkers for genomic instability and novel therapeutic targets in cancer. As a DSB related proteins considerably appear the possibilities for targeting DNA repair defective tumors or hyperactive DNA repair tumors. Based on recent research, we describe the relationship between unstable DSB repairs and DSB-related E3 ligases.