• BMB Reports
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• 제44권8호
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• pp.517-522
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• 2011

Mitochondrial dynamics not only involves mitochondrial morphology but also mitochondrial biogenesis, mitochondrial distribution, and cell death. To identify specific regulators to mitochondria dynamics, we screened a chemical library and identified niclosamide as a potent inducer of mitochondria fission. Niclosamide promoted mitochondrial fragmentation but this was blocked by down-regulation of Drp1. Niclosamide treatment resulted in the disruption of mitochondria membrane potential and reduction of ATP levels. Moreover, niclosamide led to apoptotic cell death by caspase-3 activation. Interestingly, niclosamide also increased autophagic activity. Inhibition of autophagy suppressed niclosamide-induced cell death. Therefore, our findings suggest that niclosamide induces mitochondria fragmentation and may contribute to apoptotic and autophagic cell death.

• Journal of Microbiology
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• 제42권3호
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• pp.248-252
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• 2004

In order to identify the protein(s) secreted into culture medium by the sool-l/retl-l mutation of Saccharomyces cerevisiae, proteins from the culture medium of cells grown at permissive (28$^{\circ}C$) and non-permissive temperatures (37$^{\circ}C$), were analyzed. Comparison of protein bands separated by SDS-PAGE identified a prominent band of 47-kDa band from a mutant grown at 37$^{\circ}C$. N-terminal amino acid sequencing of this 47-kDa protein showed high identity with enolases 1 and 2. Western blot analysis revealed that most of the cell wall-bound enolase was released into the culture medium of the mutant grown at 37$^{\circ}C$, some of which were separated as those with lower molecular weights. Our results, presented here, indicate the impairment of cell wall enolase biogenesis and assembly by the sool-l/retl-l mutation of S. cerevisiae.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 2001년도 The Asia-Pacific Conference on Reproductive Biology and Environmental Sciences
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• pp.49-53
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• 2001

• BMB Reports
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• 제47권5호
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• pp.280-285
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• 2014

Cancer cells undergo uncontrolled proliferation, and aberrant mitochondrial alterations. Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial heat shock protein. TRAP1 mRNA is highly expressed in some cancer cell lines and tumor tissues. However, the effects of its overexpression on mitochondria are unclear. In this study, we assessed mitochondrial changes accompanying TRAP1 overexpression, in a mouse cell line, NIH/3T3. We found that overexpression of TRAP1 leads to a series of mitochondrial aberrations, including increase in basal ROS levels, and decrease in mitochondrial biogenesis, together with a decrease in peroxisome proliferator-activated receptor gamma coactivator-$1{\alpha}$ (PGC-$1{\alpha}$) mRNA levels. We also observed increased extracellular signal-regulated kinase (ERK) phosphorylation, and enhanced proliferation of TRAP1 overexpressing cells. This study suggests that overexpression of TRAP1 might be a critical link between mitochondrial disturbances and carcinogenesis.

• BMB Reports
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• 제46권1호
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• pp.9-16
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• 2013

In mammalian cells, aberrant transcripts harboring a premature termination codon (PTC) can be generated by abnormal or inefficient biogenesis of mRNAs or by somatic mutation. Truncated polypeptides synthesized from these aberrant transcripts could be toxic to normal cellular functions. However, mammalian cells have evolved sophisticated mechanisms for monitoring the quality of mRNAs. The faulty transcripts harboring PTC are subject to nonsense-mediated mRNA decay (NMD), nonsense-mediated translational repression (NMTR), nonsense-associated alternative splicing (NAS), or nonsense-mediated transcriptional gene silencing (NMTGS). In this review, we briefly outline the molecular characteristics of each pathway and suggest mRNA quality control mechanisms as a means to regulate normal gene expression.

• Molecules and Cells
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• 제41권1호
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• pp.18-26
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• 2018

Mitochondrial quality control systems are essential for the maintenance of functional mitochondria. At the organelle level, they include mitochondrial biogenesis, fusion and fission, to compensate for mitochondrial function, and mitophagy, for degrading damaged mitochondria. Specifically, in mitophagy, the target mitochondria are recognized by the autophagosomes and delivered to the lysosome for degradation. In this review, we describe the mechanisms of mitophagy and the factors that play an important role in this process. In particular, we focus on the roles of mitophagy adapters and receptors in the recognition of damaged mitochondria by autophagosomes. In addition, we also address a functional association of mitophagy with mitochondrial dynamics through the interaction of mitophagy adaptor and receptor proteins with mitochondrial fusion and fission proteins.

• Molecules and Cells
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• 제40권12호
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• pp.889-896
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• 2017

Nuclear bodies are subnuclear, spheroidal, and membraneless compartments that concentrate specific proteins and/or RNAs. They serve as sites of biogenesis, storage, and sequestration of specific RNAs, proteins, or ribonucleoprotein complexes. Recent studies reveal that a subset of nuclear bodies in various eukaryotic organisms is constructed using architectural long noncoding RNAs (arcRNAs). Here, we describe the unifying mechanistic principles of the construction and function of these bodies, especially focusing on liquid-liquid phase separation induced by architectural molecules that form multiple weakly adhesive interactions. We also discuss three possible advantages of using arcRNAs rather than architectural proteins to build the bodies: position-specificity, rapidity, and economy in sequestering nucleic acid-binding proteins. Moreover, we introduce two recently devised methods to discover novel arcRNA-constructed bodies; one that focuses on the RNase-sensitivity of these bodies, and another that focuses on "semi-extractability" of arcRNAs.

• BMB Reports
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• 제45권1호
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• pp.7-13
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• 2012

Phospholipase D (PLD), a superfamily of signaling enzymes that most commonly generate the lipid second messenger Phosphatidic Acid (PA), is found in diverse organisms from bacteria to man and functions in multiple cellular pathways. A fascinating member of the family, MitoPLD, is anchored to the mitochondrial surface and has two reported roles. In the first role, MitoPLD-generated PA regulates mitochondrial shape through facilitating mitochondrial fusion. In the second role, MitoPLD performs a critical function in a pathway that creates a specialized form of RNAi required by developing spermatocytes to suppress transposon mobilization during meiosis. This spermatocyte-specific RNAi, known as piRNA, is generated in the nuage, an electron-dense accumulation of RNA templates and processing proteins that localize adjacent to mitochondria in a structure also called intermitochondrial cement. In this review, we summarize recent findings on these roles for MitoPLD functions, highlighting directions that need to be pursued to define the underlying mechanisms.

• BMB Reports
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• 제49권8호
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• pp.424-430
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• 2016

Autophagy, an evolutionarily conserved cellular degradation pathway of the lysosome, is associated with many physiological and pathological processes. The hallmark of autophagy is the formation of the autophagosome that engulfs and degrades cytosolic components via its fusion with the lysosome, in either a selective or a non-selective manner. Autophagy is tightly regulated by proteins encoded by autophagy-related (atg) genes. Among these proteins, ATG8/LC3 is essential for autophagosome biogenesis/maturation and it also functions as an adaptor protein for selective autophagy. In mammalian cells, several homologs of yeast Atg8 such as MAP1LC3, GABARAP, and GABARAPL 1/2 have been identified. However, the biological relevance of this gene diversity in higher eukaryotes, and their specific roles, are largely unknown. In this review, we describe the mammalian ATG8/LC3 family and discuss recent advancements in understanding their roles in the autophagic process.

• Advances in Traditional Medicine
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• 제3권2호
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• pp.80-83
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• 2003

The inhibitory effect of Atractylodis Rhizoma alba extract(AM) on melanogenesis was studied by using B16/F10 melanoma in culture. Cells were cultured in the presence of various concentrations of AM for 48 hrs, and the experiment of total melanin content as a final product and activity of tyrosinase, a key enzyme, in melanogenesis. AM significantly inhibited tyrosinase activity, and melanin content in a dose-dependent manner. These results show that Atractylodes macrocephala extract could be developed as skin whitening components of cosmetics.