• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.197-204
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• 2009

Trypanosoma brucei, a protozoan parasite, causes sleeping sickness in humans and Nagana disease in domestic animals in central Africa. The trypanosome surface is extensively covered by glycosylphosphatidylinositol (GPI)-anchored proteins known as variant surface glycoproteins and procyclins. GPI anchoring is suggested to be important for trypanosome survival and establishment of infection. Trypanosomes are not only pathogenically important, but also constitute a useful model for elucidating the GPI biosynthesis pathway. This review focuses on the trypanosome GPI biosynthesis pathway. Studies on GPI that will be described indicate the potential for the design of drugs that specifically inhibit trypanosome GPI biosynthesis.

• BMB Reports
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• v.40 no.6
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• pp.1050-1057
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• 2007

Peptide deformylase (PDF) is a metalloenzyme that removes the N-terminal formyl groups from newly synthesized proteins. It is essential for bacterial survival, and is therefore-considered as a potential target for antimicrobial chemotherapy. However, some bacteria including medically relevant pathogens possess two or more def-like genes. Here we have examined two PDFs from Bacillus cereus. The two share only 32% sequence identity and the crystal structures show overall similarity with PDF2 having a longer C-terminus. However, there are differences at the two active sites, and these differences appear to contribute to the activity difference seen between the two. BcPDF2 is found as a dimer in the crystal form with two additional actinonin bound at that interface.

• Molecules and Cells
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• v.41 no.1
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• pp.27-34
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• 2018

The cytoplasm in mammalian cells is a battlefield between the host and invading microbes. Both the living organisms have evolved unique strategies for their survival. The host utilizes a specialized autophagy system, xenophagy, for the clearance of invading pathogens, whereas bacteria secrete proteins to defend and escape from the host xenophagy. Several molecules have been identified and their structural investigation has enabled the comprehension of these mechanisms at the molecular level. In this review, we focus on one example of host autophagy and the other of bacterial defense: the autophagy receptor, NDP52, in conjunction with the sugar receptor, galectin-8, plays a critical role in targeting the autophagy machinery against Salmonella; and the cysteine protease, RavZ secreted by Legionella pneumophila cleaves the LC3-PE on the phagophore membrane. The structure-function relationships of these two examples and the directions of future research will be discussed.

• CELLMED
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• v.3 no.1
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• pp.3.1-3.3
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• 2013

The receptor activator of NF-${\kappa}B$ ligand (RANKL), a member of the tumor necrosis factor ligand family, has extensive functions beyond osteoclast development. RANKL is expressed in many immune cells such as osteoblasts, osteocytes, marrow stromal cells, activated T cells, synovial cells, keratinocytes, and mammary gland epithelial cells as well as in various tissues. The ligation of RANK by RANKL promotes dendritic cells (DCs) survival through prosurvival signals and the up-regulation of the anti-apoptotic proteins Bcl-2 and Bcl-$x_L$ and plays a crucial role in DCs-mediated Th1 differentiation. Therefore, RANKL plays an important role in the regulation of DCs/T cells-mediated specific immunity. This review will briefly inform our current understanding of the role of RANKL signaling in T cells-DCs communication in the immune system.

• YAKHAK HOEJI
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• v.48 no.1
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• pp.47-54
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• 2004

ClpP is a stress-inducible protein and proteolytic subunit of the ATP-dependent Clp protease in prokaryotes and eukaryotes. Although its physiological roles in bacterial virulence were widely studied in various organsims, including Streptococcus pneumoniae, until now the immunological effect has not been investigated. Here, we have examined the cross reactivity of S. pneumoniae ClpP antibody with other organisms's cell lysate proteins. Although the protein sequence of S. pneumoniae ClpP was highly conserved among various organisms including human, the antibody rasised by S. pneumoniae ClpP was not cross-reacted with other organism's cell lysates, which were Saccharomyces cerevisiae , human lung A549 cell, Bacillus subtilis, Pseuomonas aeruginosa, E. coli, and Salmonella typhi. It was only reacted with S. pneumoniae and Lato-bacillus thermophilus. Thus we examined the immunoprotective effect of ClpP by immunizing mice with the purified ClpP. The mean survival time of mouse was significantly increased with the ClpP immunization. These results suggest that S. pneumoniae ClpP could be used as a vaccine candidate for prevention of S. pneumoniae infection.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.147-151
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• 2000

Heat shock protein 70(HSP70) is induced by elevated temperature and many other types of stresses in cell. HSP70 ensures cell survival under stressful condition that would lead to irreversible cell damage and ultimately to cell death. HSP70 plays essential role in the synthesis, transport, and folding of proteins and is often refferred to as molecular chaperones. Increased levels of HSPs occur after arthritis, infection, imflammation, autoimmune disease and CNS injury such as infarction, ischemia, seizure and Alzheimer's disease. Also, HSP70 increases resistance to apoptosis. The recent studies that the expression of the HSP has been processed at various field. However, they an still relatively line studied in clinically application. This review summarizes the fundamental knowledge of HSP.

• BMB Reports
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• v.47 no.12
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• pp.655-659
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• 2014

Integrin-mediated cell adhesion is important for development, immune responses, hemostasis and wound healing. Integrins also function as signal transducing receptors that can control intracellular pathways that regulate cell survival, proliferation, and cell fate. Conversely, cells can modulate the affinity of integrins for their ligands a process operationally defined as integrin activation. Analysis of activation of integrins has now provided a detailed molecular understanding of this unique form of "inside-out" signal transduction and revealed new paradigms of how transmembrane domains (TMD) can transmit long range allosteric changes in transmembrane proteins. Here, we will review how talin and mediates integrin activation and how the integrin TMD can transmit these inside out signals.

• Mycobiology
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• v.43 no.3
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• pp.179-183
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• 2015

Zinc is an essential micronutrient required for many enzymes that play essential roles in a cell. It was estimated that approximately 3% of the total cellular proteins are required for zinc for their functions. Zinc has long been considered as one of the key players in host-pathogen interactions. The host sequesters intracellular zinc by utilizing multiple cellular zinc importers and exporters as a means of nutritional immunity. To overcome extreme zinc limitation within the host environment, pathogenic microbes have successfully evolved a number of mechanisms to secure sufficient concentrations of zinc for their survival and pathogenesis. In this review, we briefly discuss the zinc uptake systems and their regulation in the model fungus Saccharomyces cerevisiae and in major human pathogenic fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus gattii.

• BMB Reports
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• v.55 no.12
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• pp.577-586
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• 2022

Stress granules (SGs) are stress-induced subcellular compartments, which carry out a particular function to cope with stress. These granules protect cells from stress-related damage and cell death through dynamic sequestration of numerous ribonucleoproteins (RNPs) and signaling proteins, thereby promoting cell survival under both physiological and pathological condition. During tumorigenesis, cancer cells are repeatedly exposed to diverse stress stimuli from the tumor microenvironment, and the dynamics of SGs is often modulated due to the alteration of gene expression patterns in cancer cells, leading to tumor progression as well as resistance to anticancer treatment. In this mini review, we provide a brief discussion about our current understanding of the fundamental roles of SGs during physiological stress and the effect of dysregulated SGs on cancer cell fitness and cancer therapy.

• International Journal of Stem Cells
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• v.16 no.1
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• pp.117-122
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• 2023

Background and Objectives: mRNA-based protein expression technology has been used to express functional proteins. We have previously generated dopamine neurons from rat-embryo derived neural precursor cells (NPCs) through repeated transfection of synthetic transcription factor mRNA encoding dopamine-inducible genes. However, NPCs began to die approximately 10 d post-transfection. In this study, we examined a long-term transfection protocol that did not affect cell viability. Methods and Results: Experiments were performed in eight groups sorted according to the start date of mRNA transfection. mRNA was transfected into NPCs daily for 21 d and live cell images of each group were recorded. NPCs which were differentiated for more than five days showed sustained gene expression and appreciable viability despite daily mRNA transfection for 21 d. Conclusions: Repeated mRNA transfection requires cells with a sufficient differentiation period.