• Journal of Institute of Control, Robotics and Systems
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• v.10 no.12
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• pp.1155-1163
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• 2004

Extracellular signal-regulated kinase (ERK) signaling pathway is one of the mitogen-activated protein kinase (MAPK) signal transduction pathways. This pathway is known as pivotal in many signaling networks that govern proliferation, differentiation and cell survival. The ERK signaling pathway comprises positive and negative feedback loops, depending on whether the terminal kinase stimulates or inhibits the activation of the initial level. In this paper, we attempt to model the ERK pathway by considering both of the positive and negative feedback mechanisms based on Michaelis-Menten kinetics. In addition, we propose a fraction ratio model based on the mass action law. We first develop a mathematical model of the ERK pathway with fraction ratios. Secondly, we analyze the dynamical properties of the fraction ratio model based on simulation studies. Furthermore, we propose a concept of an inhibitor, catalyst, and substrate (ICS) controller which regulates the inhibitor, catalyst, and substrate concentrations of the ERK signal transduction pathway. The ICS controller can be designed through dynamical analysis of the ERK signaling transduction pathway within limited concentration ranges.

• BMB Reports
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• v.32 no.3
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• pp.215-225
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• 1999

Phytochromes (with gene family members phyA, B, C, D, and E) are a wavelength-dependent light sensor or switch for gene regulation that underscore a number of photo responsive developmental and morphogenic processes in plants. Recently, phytochrome-like pigment proteins have also been discovered in prokaryotes, possibly functioning as an auto-phosphorylating/phosphate-relaying two-component signaling system (Yeh et al., 1997). Phytochromes are photochromically convertible between the light sensing Pr and regulatory active Pfr forms. Red light converts Pr to Pfr, the latter having a "switch-on" conformation. The Pfr form triggers signal transduction pathways to the downstream responses including the expression of photosynthetic and other growth-regulating genes. The components involved in and the molecular mechanisms of the light signal transduction pathways are largely unknown, although G-proteins, protein kinases, and secondary messengers such as $Ca^{2+}$ ions and cGMP are implicated. The 124-127 kDa phytochromes form homodimeric structures. The N-terminal half contains the tetrapyrrolic phytochromobilin for red/far-red light absorption. The C-terminal half includes both a dimerization motif and regulatory box where the red light signal perceived by the chromophore-domain is recognized and transduced to initiate the signal transduction cascade. A working model for the inter-domain signal communication within the phytochrome molecule is proposed in this Review.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.227-238
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• 2012

Mitogen-activated protein kinase (MAPK) cascades are conserved signaling modules in the eukaryotic cells. They are involved in many major cell processes in fungi such as stress responses, vegetative growth, pathogenicity, secondary metabolism and cell wall integrity. In this review, we summarized the advances of research on the MAPK signaling pathways in Alternaria species. As major phytopathogenic fungi, Alternaria species reduce crop production. In contrast to the five MAPK pathways known in yeast, only three MAPK pathways as Fus3/Kss1-type, Hog1-type, and Slt2-type have been characterized in Alternaria. The Fus3/Kss1-type MAPK pathway participates in regulation of vegetative growth, conidiation, production of some cell-wall-degrading enzymes and pathogenicity. The Hog1-type pathway is involved in osmotic and oxidative stress, fungicides susceptibility and pathogenicity. The Slt2-type MAP kinases play an important role on maintaining cell wall integrity, pathogenicity and conidiation. Although recent advances on the MAPK pathways in Alternaria spp. reveal many important features on the pathogenicity, there are many unsolved problems regarding to the unknown MAP kinase cascade components and network among other major signal transduction. Considering the economic loss induced by Alternaria spp., more researches on the MAPK pathways will need to control the Alternaria diseases.

• The Korea Genome Conference
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• 2002.08a
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• pp.39.2-39.2
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• 2002

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05b
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• pp.73.2-87
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• 2002

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2001.10b
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• pp.29-30
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• 2001

• Proceedings of the PSK Conference
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• 2003.10a
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• pp.60-61
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• 2003

Human Genome Project has recently been completed and the information on nucleotide sequences of our whole genome is now available at the public or commercial data banks. Next goals are to identify the functions of each gene and to elucidate the intracellular signal transduction pathways regulating gene expression. We have established a PCR-based bioassay to search for biologically active compounds that can modulate the expression of genes encoding important proteins. (omitted)

• IMMUNE NETWORK
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• v.9 no.3
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• pp.75-83
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• 2009

Recent years have seen an explosion of new knowledge defining the molecular events that are critical for development and activation of immune cells. Much of this new information has come from a careful molecular dissection of key signal transduction pathways that are initiated when immune cell receptors are engaged. In addition to the receptors themselves and critical effector molecules, these signaling pathways depend on adapters, proteins that have no intrinsic effector function but serve instead as scaffolds to nucleate multimolecular complexes. This review summarizes some of what has been learned about one such adapter protein, SH2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76), and how it regulates and integrates signals after engagement of immunoreceptors and integrins on various immune cell lineages.

• Journal of fish pathology
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• v.20 no.1
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• pp.71-81
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• 2007

Photobacterium damselae subsp. damselae and 4 Vibrio spp.(V. anguillarum, V. splendidus, V. harveyi and V. ordalii) were isolated from the diseased olive flounders, Paralichthys olivaceus. The isolates were tested on the pathogenicity in vitro. The properties of extracellular products(ECPs) were investigated with enzymatic activities, hemolytic activities toward the sheep and olive flounder erythrocytes, and cytotoxicity activities on the cell-line. And potential signal transduction pathways of the bacterial internalization were detected by using signal transduction inhibitors. P. damselae was high in phospholipase activity, hemolytic activity to olive flounder erythrocytes and cytotoxicity activity. And P. damselae had diversified internalizing pathways as compared to isolated vibrios. Therefore, these activities may be related with pathogenicity of P. damselae.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.123-127
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• 1996

Secretion of surfactant phospholipid can be stimulated by a variety of agonists acting via at least three different signal transduction mechanisms. These include the adenylate cyclase system with activation of cAMP-dependent protein kinase; activation of protein kinase C either directly or subsequent to activation of phosphoinositide-specific phospholipase C and generation of diacylglycerols and inositol trisphosphate; and a third mechanism that involves incresed $Ca^{2+}$ levels and a calmodulin-dependent step. ATP stimulates secretion via all three mechanisms. The protein kinase C pathway is also coupled to phopholipase D which, acting on relatively abundant cellular phospholipids, generates diacylglycerols that further activate protein kinase C. Sustained protein kinase C activation can maintain phosphatidylcholine secretion for a prolonged period of time. It is likely that interactions between the different signaling pathways have an important role in the overall physiological regulation of surfactant secretion.