• Journal of Microbiology and Biotechnology
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• 제24권7호
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• pp.914-920
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• 2014

Triple-negative breast cancer (TNBC) possesses a higher rate of distant recurrence and a poorer prognosis than other breast cancer subtypes. Interestingly, most of the heat shock protein 90 (Hsp90) client proteins are oncoproteins, and some are closely related to unfavorable factors of TNBC patients. 17-Demethoxy-reblastatin (17-DR), a novel non-benzoquinone-type geldanamycin analog, exhibited potent Hsp90 ATPase inhibition activity. In this study, the anticancer effects of 17-DR on TNBC MDA-MB-231 cells were investigated. These results showed that 17-DR inhibited cell proliferation, induced apoptosis, and suppressed cell invasion and migration in the MDA-MB-231 cells. Down-regulation of the key Hsp90-dependent tumor-driving molecules, such as RIP1 and MMP-9, by 17-DR may be related to these effects. Taken together, our results suggest that 17-DR has potential as a therapeutic agent for the treatment of TNBC.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.351-357
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• 2009

Natural wild-type strains of Bacillus subtilis are extensively used in agriculture as biocontrol agents for plants. This study examined two antagonist B. subtilis strains, KB-1111 and KB-1122, and the results illustrated that KB-1122 was a more potent inhibitor of the indicator pathogen than KB-1111. Thus, to investigate the intrinsic differences between the two antagonist strains under normal culture conditions, samples of KB-1111 and KB-1122 were analyzed using MALDI-TOF-MS. The main differences were related to 20 abundant intracellular and 17 extracellular proteins. When searching the NCBI database, a number of the differentially expressed proteins were identified, including 11 cellular proteins and 10 secretory proteins. Among these proteins, class III stress-response-related ATPase, aconitate hydratase, alpha-amylase precursor, and a secretory protein, endo-l, 4-beta-glucanase, were differentially expressed by the two strains. These results are useful to comprehend the intrinsic differences between the antagonism of KB-1111 and KB-1122.

• BMB Reports
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• 제42권7호
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• pp.450-455
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• 2009

The "stage albinism line of winter wheat" FA85 was a specific natural mutant strain on leaf color. This physiological mutation was controlled by cytogene. In order to reveal the genetic and biochemical mechanism of albinism, 2-DE was used to investigate the difference of chloroplast protein expression pattern between FA85 and its parent wheat Aibian 1. From the results of 2-DE gels analysis, approximately 683 spots were detected on each gel, and 57 spots were expressed differently at least two-fold. Using MALDI-TOF/TOF MS, 14 of 57 spots were identified, which could be categorized into four classes: carbon metabolism, energy metabolism, defense/stress response and signal transduction. Compared with the parent wheat, the expression of ATPase-$\gamma$ and GP1-$\alpha$ was up-regulated in FA85, and of other proteins was down-regulated. Together, we concluded that the expression of chloroplast proteins had changed obviously in FA85, which might be related to the leaf color mutant.

• Molecules and Cells
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• 제27권3호
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• pp.307-312
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• 2009

The interstitial cells of Cajal (ICC) are pacemaking cells required for gastrointestinal motility. The possibility of whether DA-9701, a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber, modulates pacemaker activities in the ICC was tested using the whole cell patch clamp technique. DA-9701 produced membrane depolarization and increased tonic inward pacemaker currents in the voltage-clamp mode. The application of flufenamic acid, a non-selective cation channel blocker, but not niflumic acid, abolished the generation of pacemaker currents induced by DA-9701. Pretreatment with a $Ca^{2+}$-free solution and thapsigargin, a $Ca^{2+}$-ATPase inhibitor in the endoplasmic reticulum, abolished the generation of pacemaker currents. In addition, the tonic inward currents were inhibited by U-73122, an active phospholipase C inhibitor, but not by $GDP-{\beta}-S$, which permanently binds G-binding proteins. Furthermore, the protein kinase C inhibitors, chelerythrine and calphostin C, did not block the DA-9701-induced pacemaker currents. These results suggest that DA-9701 might affect gastrointestinal motility by the modulation of pacemaker activity in the ICC, and the activation is associated with the non-selective cationic channels via external $Ca^{2+}$ influx, phospholipase C activation, and $Ca^{2+}$ release from internal storage in a G protein-independent and protein kinase C-independent manner.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2006년도 International Meeting of the Microbiological Society of Korea
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• pp.66-68
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• 2006

SUF machinery in Echerichia coli, responsible for the biosynthesis of iron-sulfur clusters, is composed of six protein components (SufABCDSE), among which SufB, SufC, and SufD associate in a complex. We have determined the structures of SufA, SufC, and SufD by X-ray crystallography. SufA is a dimer, in which C-terminal segments containing essential cysteine residues (Cys-Gly-Cys) are positioned to allow coordination of an Fe-S cluster and/or an Fe atom. SufC has the overall structure similar to that of ABC-ATPase but takes an inactive form. SufD has a ${\beta}-helix$ flanked with a-helical domains. We also studied the functional roles of the residues in SufD by mutagenesis and determined the crystal structure of SufCD complex. Molecular mechanism of Fe-S cluster biosynthesis is discussed on the basis of the structural and functional evidence.

• BMB Reports
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• 제34권6호
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• pp.573-577
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• 2001

The mammalian heart is known to undergo significant mechanical changes during fetal and neonatal development. The objective of this study was to define the ontogeny of the ryanodine receptor/$Ca^{2+}$ release channel and SERCA that play the major roles in excitation-contraction coupling. Whole ventricular homogenates of fetal (F) (19 and 22 days in gestation), postnatal (N) (1 and 7 days postnatal), and adult (A) (5 weeks postnatal) Sprague-Dawley rat hearts were used to study [$^3H$]ryanodine binding and oxalate-supported $^{45}Ca^{2+}$ uptake. For the ryanodine receptor, the major findings were: (1) The ryanodine receptor density, as determined by maximal [$^3H$]ryanodine binding ($B_{max}$), increased 3 fold between the F22 and A periods ($0.26{\pm}0.1$ vs. $0.73{\pm}0.07$ pmoles/mg protein, p<0.01), whereas there was no significant change during the F22 and N1 development phases ($0.26{\pm}0.1$ vs. $0.34{\pm}0.01$). (2) Affinity of the ryanodine receptor to ryanodine did not significantly change, as suggested by the lack of change in the $K_d$ during the development and maturation. For SERCA, changes started early with an increased rate of $Ca^{2+}$ uptake in the fetal periods (F19: $8.1{\pm}1.1$ vs. F22: $19.3{\pm}2.2$ nmoles/g protein/min; p<0.05) and peaked by 7 days (N7) of the postnatal age ($34.9{\pm}2.1$). Thus, we conclude that the quantitative changes occur in the ryanodine receptor during myocardial development. Also, the maturation of the $Ca^{2+}$ uptake appears to start earlier than that of the $Ca^{2+}$ release.

• The Korean Journal of Physiology and Pharmacology
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• 제12권1호
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• pp.25-30
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• 2008

Although many studies show that thromboxane $A_2\;(TXA_2)$ has the action of gastrointestinal (GI) motility using GI muscle cells and tissue, there are no reports on the effects of $TXA_2$ on interstitial cells of Cajal (ICC) that function as pacemaker cells in GI tract. So, we studied the modulation of pacemaker activities by $TXA_2$ in ICC with whole cell patch-clamp technique. Externally applied $TXA_2\;(5{\mu}M)$ produced membrane depolarization in current-clamp mode and increased tonic inward pacemaker currents in voltage-clamp mode. The tonic inward currents by $TXA_2$ were inhibited by intracellular application of GDP-${\beta}$-S. The pretreatment of ICC with $Ca^{2+}$ free solution and thapsigargin, a $Ca^{2+}$-ATPase inhibitor in endoplasmic reticulum, abolished the generation of pacemaker currents and suppressed the $TXA_2$-induced tonic inward currents. However, chelerythrine or calphostin C, protein kinase C inhibitors, did not block the $TXA_2$-induced effects on pacemaker currents. These results suggest that $TXA_2$ can regulate intestinal motility through the modulation of ICC pacemaker activities. This modulation of pacemaker activities by $TXA_2$ may occur by the activation of G protein and PKC independent pathway via extra and intracellular $Ca^{2+}$ modulation.

• BMB Reports
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• 제51권8호
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• pp.378-387
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• 2018

Skeletal muscle contracts or relaxes to maintain the body position and locomotion. For the contraction and relaxation of skeletal muscle, $Ca^{2+}$ in the cytosol of skeletal muscle fibers acts as a switch to turn on and off a series of contractile proteins. The cytosolic $Ca^{2+}$ level in skeletal muscle fibers is governed mainly by movements of $Ca^{2+}$ between the cytosol and the sarcoplasmic reticulum (SR). Store-operated $Ca^{2+}$ entry (SOCE), a $Ca^{2+}$ entryway from the extracellular space to the cytosol, has gained a significant amount of attention from muscle physiologists. Orai1 and stromal interaction molecule 1 (STIM1) are the main protein identities of SOCE. This mini-review focuses on the roles of STIM proteins and SOCE in the physiological and pathophysiological functions of skeletal muscle and in their correlations with recently identified proteins, as well as historical proteins that are known to mediate skeletal muscle function.

• 동의생리병리학회지
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• 제27권1호
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• pp.112-117
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• 2013

We studied the modulation of pacemaker activities by Samchulkunbi-tang (SCKB) in cultured interstitial cells of Cajal (ICC) from murine small intestine with the whole-cell patch-clamp technique. Externally applied SCKB produced membrane depolarization in the current-clamp mode. The pretreatment with $Ca^{2+}$-free solution and thapsigargin, a $Ca^{2+}$-ATPase inhibitor in endoplasmic reticulum, abolished the generation of pacemaker potentials and suppressed the SCKB-induced action. The application of flufenamic acid (a nonselective cation channel blocker) abolished the generation of pacemaker potentials by SCKB. However, the application of niflumic acid (a chloride channel blocker) did not inhibit the generation of pacemaker potentials by SCKB. In addition, the membrane depolarizations were inhibited by not only GDP-${\beta}$-S, which permanently binds G-binding proteins, but also U-73122, an active phospholipase C inhibitor. These results suggest that SCKB modulates the pacemaker activities by nonselective cation channels and external $Ca^{2+}$ influx and internal $Ca^{2+}$ release via G-protein and phospholipase C-dependent mechanism. Therefore, the ICC are targets for SCKB and their interaction can affect intestinal motility.

• Journal of Photoscience
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• 제11권3호
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• pp.121-127
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• 2004

The${\beta}$-glucosidases occur widely in all living organisms and has in general a tendency to form oligomers of varying numbers of subunits or aggregates, although the functional implications of such diverse oligomerization schemes remain unclear. In particular, the assembly mode of the oat ${\beta}$-glucosidase is very unique in that it multimerizes by linear stacking of a hexameric building block to form long fibrillar multimers. Some structural proteins such as actin and tubulin assemble into long fibrils in a helical fashion and several enzymes such as GroEL and Pyrodictium ATPase functional complexes, 20S proteasome of the archaebacterium Thermoplasma acidophilum, and lutamine synthetase fromblue-green algae, assemble into discrete oligomers upto 4 stacked rings to maintain their enzymatic activities. In particular, oat ${\beta}$-glucosidase exists in vivo as a discrete long fibrillar multimer assembly that is a novel structure for enzyme protein. It is assembled by linear stacking of hollow trimeric units. The fibril has a long central tunnel connecting to the outer medium via regularly distributed side fenestrations. The enzyme active sites are located within the central tunnel and multimerization increases enzyme affinity to the substrates and catalytic efficiency of the enzyme. Although it is suggested that oligomerization may contribute to the enzyme stability and catalytic efficiency of ${\beta}$-glycosidases, the functional implications of such diverse oligomerization schemes remain unclear so far.