Insulin Cannot Activate Extracellular-signal-related Kinase Due to Inability to Generate Reactive Oxygen Species in SK-N-BE(2) Human Neuroblastoma Cells

허규정,황정진 한국분자세포생물학회 2005 Molecules and cells Vol.20 No.2

The insulin-mediated Ras/mitogen-activated protein (MAP) kinase cascade was examined in SK-N-BE(2) and PC12 cells, which can and cannot produce reactiveoxygen species (ROS), respectively. Tyrosine phosphorylation of the insulin receptor and insulin receptor substrate 1 (IRS-1) was much lower in SK-NBE(2) cells than in PC12 cells when the cells were treated with insulin. The insulin-mediated interaction of IRS-1 with Grb2 was observed in PC12 but not in SK-N-BE(2) cells. Moreover, the activity of extracellular- signal-related kinase (ERK) was much lower in SK-N-BE(2) than in PC12 cells when the cells were treated with insulin. Application of exogenous H2O2 caused increased tyrosine phosphorylation and Grb2 binding to IRS-1 in SK-N-BE(2) cells, while exposure to an H2O2 scavenger (N-acetylcysteine) or to a phophatidylinositol-3 kinase inhibitor (wortmannin), and expression of a dominant negative Rac1, decreased the activation of ERK in insulin-stimulated PC12 cells. These results indicate that the transient increase of ROS is needed to activate ERK in insulin-mediated signaling and that an inability to generate ROS is the reason for the insulin insensitivity of SK-N-BE(2) cells.

Gap junction 을 통한 세포간의 정보교환

허규정 생화학분자생물학회 1988 생화학분자생물학회 소식 Vol.8 No.3

Gap Junction 을 통한 세포간의 정보교환

허규정 ( Kyu Jung Huh ) 생화학분자생물학회 1991 생화학총설집 Vol.3 No.-

cAMP Dependent Protein Kinase에 의한 Adenylate Cyclase의 억제

許圭晶 梨花女子大學校 韓國生活科學硏究院 1992 韓國生活科學硏究院 論叢 Vol.50 No.-

To figure out possible roles of protein kinase A in the process of adenylate cyclase-desensitization, Ca^2+/calmodulin-sensitive adenylate cyclase was isolated from the membranes of lens fiber cells using calmodulin affinity column. The isolated adenylate cyclase which is free from GTP binding preteins, was gradually activated by various concentrations of calmodulin. However, the activity of adenylate cyclase was dramatically decreased in the presence of protein kinase A. Especially, stimulation of the activity of adenylate cyclase by calmodulin was almost abolished in the presence of protein kinase A. These results suggest that protein kinase A phosphorylates catalytic subunit of adenylate cyclase, and then inactivates enzyme activity.

Small GTP-binding Proteins

許奎晶 한국식물학회 1990 Journal of Plant Biology Vol.33 No.3

There is a family of homologous proteins known to small GTP-inding proteins which have a GTP binding domains and GTPase activity with molecular weight of about 20000 in mammalian tissues. Recently at least 20 different small GTP-binding proteins including three ras proto-oncogene, smg25, rho, and ral gene products were identified. These porteins play a central role in cellular proliferation, neoplasia, signal transduction, terminal differentiation, and secretory process of the cells. In this review, I have briefly compiled current information on the different areas of research in the small GTP-binding proteins in an attempt to convey an overall view of the fundamental role that this family of protein in normal cellular processes. Moreover, furture goals of research in the small GTP-binding proteins as well as the possible existence of this family of proteins in plant cells were discussed.

Symposia / S4-5 : Analyses of Insulin mediated signaling mechanisms in SK-N-BE(2) human neuroblastoma cells

허규정(K . C . Hur),(J . J . Hwang),(J . Y . Sung),(K . Y . Lee) 한국생화학분자생물학회 (구 한국생화학회) 1999 생화학분자생물학회 춘계학술발표논문집 Vol.- No.-

SSR Mapping of Genes Conditioning Soybean Resistance to Six Isolates of Xanthomonas axonopodis pv. Glycines

반규정,하보균,김문영,문중경,백남천,허성기,이석하 한국유전학회 2004 Genes & Genomics Vol.26 No.1

대두 유식물에서 Protein Kinase C에 의해서 인산화되는 단백질이 동정

崔允僖,許圭晶,李埈承 이화여자대학교 생명과학연구소 1992 생명과학연구논문집 Vol.3 No.-

DEAE-52 cellulose column을 이용하여 부분적으로 분리한 PKC를 이용하여 대두 유 식물 하배축 정단부와 뿌리에서 각각 분리한 세포질 단백질과 막 단백질의 인산화 실험을 통해 PKC의 기질이 되는 단백질을 조사하여 보았다. PKC의 기질은 세포질 단백질의 경우 100, 63 그리고 41Kd 단백질들이며, 막 단백질 중 하배축 정단부의 경우는 140, 110, 66, 47 그리고 32Kd 단백질들이며, 뿌리의 경우는 140,110, 66, 47, 33, 31, 16Kd 단백질들이라고 생각된다. The previous report (Chung and Lee, 1992) in our laboratory demonstrated that the protein kinase C(PKC) activator, TPA, promotes the elongation of corn coleoptiles significantly. To understand the role of TPA on the growth, substrates of PKC were investigated using PKC partially purified from soybean by DEAE-52 cellulose column. The enzyme activity increased about 5-fold in the presence of Ca^2+ alone. The decrease in phosphorylation of 100, 61 and 43 Kd proteins of the cytosol, and 140, 110, 66, 47 and 32Kd membrane proteins in hypocotyls, and 140, 110, 66, 47, 33, 31 and 16 Kd membrane proteins in hypocotyls, and 140, 110, 66, 47, 33, 31 and 16Kd membrane proteins in the root was observed in the presence of PKC inhibitor staurosporine (STA). These results suggest that subatrates of PKC in soybean may be 110, 63 and 41Kd proteins of the cytosol, and 140,110, 66, 47 and 32Kd membrane proteins in the subapical region of the hypocotyl, and 140,110, 66, 47, 33, 31 and 16Kd membrane proteins of the root.

Role of Extracellular Matrix Proteins on the Differentiation of the F9 Embryonal Carcinoma Cells

Lee, Ho-Young,Hur, Kyu-Chung,Kim, Kyu-Won 부산대학교 유전공학연구소 1992 분자생물학 연구보 Vol.8 No.-

In order to investigate the role of extracellular matrix (ECM) proteins in differentiation of F9 embryonal carcinoma (EC) cells, we have analyzed the expression of extracellular matrix components during the differentiation of F'9 cells induced by retinoic acid (RA) and dibutyryl cyclic AMP (dbcAMP). The mRNA level of type IV collagen increased markedly and that of fibronectin decreased after the differentiation of F9 cells induced by RA and dbcAMP. The induced expression of laminin B1 in differentiated F9 cells did not change upon removal of RA and dbcAMP from culture medium. In addition, the effect of ECM components on the morphological behavior of F9 EC cells was examined by culturing F9 EC cells on the ECM-coated culture flask When F9 EC cells were cultured on laminin- and laminin/type IV collagen-coated culture flasks, they rapidly formed a round cell morphology similar to the F9 cells differentiated by RA and dbcAMP. In contrast, F9 cells cultured on a fibronectin-coated flask grew packed colonies and exhibited a flattened appearance like the morphology of F9 EC cells. These results suggest that ECM proteins, laminin and type IV collagen, are important in the morphological change and differentiation of F9 EC cells. Moreover, employing immunofluorescence analysis, we proved that the distribution pattern of cytoskeletal protein, tubulin, markedly changed through the differentiation process of F9 cells. This result suggested that cytoskeletal proteins might interconnect with ECM molecules and these ECM-cytoskeletal linkages are most likely critical for morphological change of F9 cells.

Expression of Laminin During the Differentiation of F9 Teratocarcinoma Stem Cell

Lee, Ho-Young,Hur, Kyu-Chung,Kim, Kyu-Won 이화여자대학교 생명과학연구소 1990 생명과학연구논문집 Vol.1 No.-

본 실험은 레티노익산에 의해 F9 teratocarcinoma stem cell의 분화를 유도하고 이 분화과정에서 세포형태의 변화와 라미닌유전자의 발현을 조사하였다. 분화되지 않은 F9 stem cell은 지속적으로 증식을 하며 세포간의 간격을 구분하기 어려울 뿐만 아니라 불규칙적인 모양을 하고 있으나, 레티노익산과 dibutyryl cyclic AMP처리후의 분화된 F9 세포는 둥글고 평평한 모양을 나타내며 세포성장은 중지되었다. Northern blot분석에 의하여 레티노익산과 cyclic AMP처리 후의 F9 세포에서 라미닌 유전자의 발현은 현저하게 증가하였다. 즉, 라미닌 B1유전자 발현은 분화과정 동안 최소한 30배, 라미닌 B2유전자의 발현은 약 20배 증가하였다. 또한 라미닌 항체를 이용한 면역형광 분석결과는 Northern분석결과와 일치하게 분화후에 라미닌 단백질 합성이 크게 증가되어 있었으며, 생성된 라미닌 단백질은 거의 세포면에 분포된 것으로 나타났다. 이러한 결과들로부터, 레티노익산에 의해 F9 stem cell의 분화가 유도되며 이 분화과정에서의 형태적인 변화와 분화의 진행은 라미닌의 생성과 밀접한 관련이 있다고 추측된다. In order to investigate the retinoic acid induced-differentiation of F9 teratocarcinoma stem cell, we have analyzed the change of cell morphology and laminin expression after exposure to retinoic acid and cyclic AMP. It is shown that undifferentiate F9 stem cells grow as closely packed colonies, and it is difficult to distinguish cell-cell boundaries. After retinoic acid and dibutyryl cyclic AMP treatment, F9 cells assume a flat morphology characterized by perinuclear granules and arrest growth. According to Northern blot analysis, laminin expression was increased markedly after retionoic acid treatment. Laminin B1 gene expression was increased at least 30-fold and laminin B2 gene expression was increased approximately 20-fold during differentiation process. Employing immunofluoresence analysis, it was proved that the synthesis of laminin protein was low level in F9 stem cell whereas it became high level in retinoic acid treated F9 cell and the laminin protein was largely accumulated in the cell surface. Our results suggest that induction of laminin B1 and B2 genes in F9 cells is retinoic acid-mediated control, and morphological change and differentiation of F9 cells might be associated with laminin gene expression.