• BMB Reports
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• 제34권6호
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• pp.517-525
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• 2001

Six renaturable protein kinases that utilize the myelin basic protein (MBP) as a substrate were activated during prolonged exposure of cardiac myocytes to okadaic acid (OA). We characterized the substrate preference and activation of these kinases, with particular emphasis on 3 novel kinases-MBPK-55, MBPK-62 and MBPK-87. The transcription factors c-Jun, Elk, ATF2, and c-Fos that are used to assess mitogen-activated protein kinase activation were all poor substrates for these three kinases. MAPKAPK2 was also not phosphorylated. In contrast, Histone IIIS was phosphorylated by MBPK-55 and MBPK-62. These protein kinases were activated in cultured cardiac fibroblasts, H9c2 cardiac myoblasts, and Cos cells. High concentrations (0.5 to $1\;{\mu}M$) of OA were essential for the activation of the protein kinases in all of the cell types examined, whereas calyculin A [an inhibitor of protein phosphatase 1 (PP1) and PP2A], cyclosporin A (a PP2B inhibitor), and an inactive OA analog all failed to activate these kinases. The high dose of okadaic acid that is required for kinase activation was also required for phosphatase inhibition, as assessed by immunoblotting whole cell lysates with anti-phosphothreonine antibodies. A variety of chemical inhibitors, including PD98059 (MEK-specific), genistein (tyrosine kinase-specific) and Bisindolylmaleimide I (protein kinase C-specific), failed to inhibit the OA activation of these kinases. Thus, MBPK-55 and MBPK-62 are also Histone IIIS kinases that are widely expressed and specifically activated upon exposure to high OA concentrations.

• 한국동물학회지
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• 제37권1호
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• pp.130-136
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• 1994

Although alteration in protein phosphorylation by specific protein kinases is of importance in transducing cellular signals in a variety of neural/endocrine systems, little is known about protein phosphorylation in the hvpothalamus. The present study aims to explore whether activation of the second messenger-dependent protein kinases affects phosphorylation of specific proteins using a cell free phosphorylation system followed by SDS-polvacrylamide gel electrophoresis. Cytoplasmic fractions derived from hvpothalami of immature rats were used as substrates and several activators and/or inhibitors of CAMP-, phosphatidylinositol- and Ca2+-calmodulin-dependent protein kinases were assessed. Many endogenous proteins were extensively phosphorylated and depending on the signal transduction pathways, phosphorvlation profiles were markedly different. The present data indicate that extracellular signals may affect cellular events through protein phosphorylation by second messengers-protein kinases in the rat hypothalamus.

• 한국미생물·생명공학회지
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• 제35권2호
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• pp.112-117
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• 2007

Protein kinase는 진핵생물과 원핵생물을 포함하는 모든 생명체에서 세포생존에 절대적으로 중요한 조절 기능을 담당한다. 일반적으로 원핵생물은 histidine 과 aspartic acid kinase로 구성된 bacterial two-component regulatory system에 의하여 환경변화에 따른 유전자의 발현이 조절되지만, 방선균을 비롯한 고등 원핵생물에서는 진핵생물성의 serine/threonine kinase들이 세포분화와 같은 분화과정을 조절하고 있다. Streptomycin 생산균인 Streptomyces griseus 균주에서도 다양한 serine/threonine kinase들이 존재하는 것으로 추정되며, 이들의 기능을 밝히는 것은 생명현상을 이해하는 중요한 열쇠를 제공해 줄 것으로 기대된다. 따라서, S. griseus로부터 protein kinase 를 동정하는 연구를 실시하였으며, 기존의 복잡한 chromatography법의 단점을 보완하기 위해 anti-phosphothreonine, anti-phosphoserine, anti-phosphotyrosine antibody를 이용한 immunoaffinity column chromatography 방법을 도입하였다. 실험 결과 약 14, 29, 31, 35, 40, 52, 56, 60 kDa의 단백질을 효과적으로 동정 할 수 있었으며, nonradioactive protein kination assay 방법으로 이들의 인산화능을 확인하였다.

• 한국동물학회지
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• 제33권2호
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• pp.141-151
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• 1990

Raf protein kinases and protein kinase C는 세포질내 serine/threonine-specific protein에 속한다. 그리고 기능적인 구조와 세포내의 분포 양상은 서로 비슷하다. Raf family oncogene를 발현시키는 a-raf와 c-raf protein kinase에 대한 antibodies로써 남생이 대뇌의 raf protein kinase의 분포를 조사하였다. 일반적으로 raf protein kinase는 제한된 지역에서 즉,general pallium,hippocampal formation, pdmordiuin hippocampi,nucleus of lateral olfactory tract, basal amygdaloid nucleus와bed of stria terminalis에 나타났으며, c-raf protein kinase의 면역학적 labeling은 a-raf보다 그 범위가 넓었다. 그렇지만 labeling되는 intensity는 오히려 a-raf보다 낮았다. 그런데 a-raf에서 가장 명확한 좋은 예는 basal amygdaloid nucleus내의 구형모양의 세포인데, 이 세포는 세포질이 매우 강하게 labeling되어 지므로 ring모양과 같이 나타났다. 특히 c-raf는 protein kinase C 가 많이 나타나는 pyramidal 세포나 Purkinje세포에 많이 존재하는 것을 볼 때 protein kinase에 의하여 활성화되는 myc와 서로 상협작용을 유도한다고 제안하는 바이다.

• Journal of Plant Biotechnology
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• 제45권4호
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• pp.315-321
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• 2018

Molecular and functional characterization of proteins and their levels is of great interest in understanding the mechanism of diverse cellular processes. In this study, we report on the convenient Escherichia coli-based protein expression system that allows recombinant of soluble proteins expression and cytosolic domain of membrane-localised kinases, followed by the detection of autophosphorylation activity in protein kinases. This approach is applied to regulatory proteins of Arabidopsis thaliana, including 14-3-3, calmodulin, calcium-dependent protein kinase, TERMINAL FLOWER 1(TFL1), FLOWERING LOCUS T (FT), receptor-like cytoplasmic kinase and cytoplasmic domain of leucine-rich repeat-receptor like kinase proteins. Our Western blot analysis which uses phospho-specific antibodies showed that five putative LRR-RLKs and two putative RLCKs have autophosphorylation activity in vitro on threonine and/or tyrosine residue(s), suggesting their potential role in signal transduction pathways. Our findings were also discussed in the broader context of recombinant expression and biochemical analysis of soluble and membrane-localised receptor kinases in microbial systems.

• 한국수정란이식학회지
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• 제30권1호
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• pp.33-43
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• 2015

Successful somatic cell nuclear transfer (SCNT) has been reported across a range of species using a range of recipient cells including enucleated metaphase II (MII) arrested oocytes, enucleated activated MII oocytes, and mitotic zygotes. However, the frequency of development to term varies significantly, not only between different cytoplast recipients but also within what is thought to be a homogenous population of cytoplasts. One of the major differences between cytoplasts is the activities of the cell cycle regulated protein kinases, maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK). Dependent upon their activity, exposure of the donor nucleus to these kinases can have both positive and negative effects on subsequent development. Co-ordination of cell cycle stage of the donor nucleus with the activities of MPF and MAPK in the cytoplast is essential to avoid DNA damage and maintain correct ploidy. However, recent information suggests that these kinases may also effect reprogramming of the somatic nucleus and preimplantation embryo development by other mechanisms. This article will summarise the differences between cytoplast recipients, their effects on development and discuss the potential role/s of MPF and or MAPK in nuclear reprogramming.

• Molecules and Cells
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• 제28권3호
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• pp.195-200
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• 2009

Protein tyrosine kinases (PTKs) play a central role in the modulation of a wide variety of cellular events such as differentiation, proliferation and metabolism, and their unregulated activation can lead to various diseases including cancer and diabetes. PTKs represent a diverse family of proteins including both receptor tyrosine kinases (RTKs) and non-receptor tyrosine kinases (NRTKs). Due to the diversity and important cellular roles of PTKs, accurate classification methods are required to better understand and differentiate different PTKs. In addition, PTKs have become important targets for drugs, providing a further need to develop novel methods to accurately classify this set of important biological molecules. Here, we introduce a novel statistical model for the classification of PTKs that is based on their structural features. The approach allows for both the recognition of PTKs and the classification of RTKs into their subfamilies. This novel approach had an overall accuracy of 98.5% for the identification of PTKs, and 99.3% for the classification of RTKs.

• The Korean Journal of Physiology and Pharmacology
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• 제6권3호
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• pp.155-160
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• 2002

It is not known whether gender differences play a role in susceptibility to ischemic acute renal failure. Thus, we examined if there were any differences in susceptibility between male and female mice to kidney ischemic injury, and if so, whether it is due to differences in mitogen activated protein kinases (MAPKs) or inflammatory responses to ischemia. Female mice were protected against kidney ischemia when compared with males. Thirty minutes of bilateral ischemia resulted in marked functional and morphological damages in males, but not in females. The ischemia-induced phosphorylation of c-jun N-terminal stress-activated protein kinases (JNKs) was higher in males than in females. Phosphorylation of extracellular signal-regulated kinases (ERKs) was lower in males than in females. Post- ischemia medullary infiltration of RAW 264.7 cell, a monocyte-macrophage cell, and intercellular adhesion molecule-1 (ICAM-1) were greater in males than in females. In conclusion, males were much more susceptible to ischemia than females. The enhanced propensity to ischemic injury in males was correlated with greater activation of JNKs, greater expression of ICAM-1, and greater trapping of leukocytes in the medulla.

• The Korean Journal of Physiology and Pharmacology
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• 제22권3호
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• pp.225-234
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• 2018

Adenosine is a naturally occurring breakdown product of adenosine triphosphate and plays an important role in different physiological and pathological conditions. Adenosine also serves as an important trigger in ischemic and remote preconditioning and its release may impart cardioprotection. Exogenous administration of adenosine in the form of adenosine preconditioning may also protect heart from ischemia-reperfusion injury. Endogenous release of adenosine during ischemic/remote preconditioning or exogenous adenosine during pharmacological preconditioning activates adenosine receptors to activate plethora of mechanisms, which either independently or in association with one another may confer cardioprotection during ischemia-reperfusion injury. These mechanisms include activation of $K_{ATP}$ channels, an increase in the levels of antioxidant enzymes, functional interaction with opioid receptors; increase in nitric oxide production; decrease in inflammation; activation of transient receptor potential vanilloid (TRPV) channels; activation of kinases such as protein kinase B (Akt), protein kinase C, tyrosine kinase, mitogen activated protein (MAP) kinases such as ERK 1/2, p38 MAP kinases and MAP kinase kinase (MEK 1) MMP. The present review discusses the role and mechanisms involved in adenosine preconditioning-induced cardioprotection.

• BMB Reports
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• 제45권12호
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• pp.700-706
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• 2012

Obesity is a worldwide epidemic as well as being a major risk factor for diabetes, cardiovascular diseases and several types of cancers. Obesity is mainly due to the overgrowth of adipose tissue arising from an imbalance between energy intake and energy expenditure. Adipose tissue, primarily composed of adipocytes, plays a key role in maintaining whole body energy homeostasis. In view of the treatment of obesity and obesity-related diseases, it is critical to understand the detailed signal transduction mechanisms of adipogenic differentiation. Adipogenic differentiation is tightly regulated by many key signal cascades, including insulin signaling. These signal cascades generally transfer or amplify the signal by using serial tyrosine phosphorylations. Thus, protein tyrosine kinases and protein tyrosine phosphatases are closely related to adipogenic differentiation. Compared to protein tyrosine kinases, protein tyrosine phosphatases have received little attention in adipogenic differentiation. This review aims to highlight the involvement of protein tyrosine phosphatases in adipogenic differentiation and the possibility of protein tyrosine phosphatases as drugs to target obesity.