Involvement of S6K1 in mitochondria function and structure in HeLa cells

Park, J.,Tran, Q.,Mun, K.,Masuda, K.,Kwon, S.H.,Kim, S.H.,Kim, D.H.,Thomas, G.,Park, J. Pergamon Press ; Elsevier Science Ltd 2016 Cellular signalling Vol.28 No.12

The major biological function of mitochondria is to generate cellular energy through oxidative phosphorylation. Apart from cellular respiration, mitochondria also play a key role in signaling processes, including aging and cancer metabolism. It has been shown that S6K1-knockout mice are resistant to obesity due to enhanced beta-oxidation, with an increased number of large mitochondria. Therefore, in this report, the possible involvement of S6K1 in regulating mitochondria dynamics and function has been investigated in stable lenti-shS6K1-HeLa cells. Interestingly, S6K1-stably depleted HeLa cells showed phenotypical changes in mitochondria morphology. This observation was further confirmed by detailed image analysis of mitochondria shape. Corresponding molecular changes were also observed in these cells, such as the induction of mitochondrial fission proteins (Drp1 and Fis1). Oxygen consumption is elevated in S6K1-depeleted HeLa cells and FL5.12 cells. In addition, S6K1 depletion leads to enhancement of ATP production in cytoplasm and mitochondria. However, the relative ratio of mitochondrial ATP to cytoplasmic ATP is actually decreased in lenti-shS6K1-HeLa cells compared to control cells. Lastly, induction of mitophagy was found in lenti-shS6K1-HeLa cells with corresponding changes of mitochondria shape on electron microscope analysis. Taken together, our results indicate that S6K1 is involved in the regulation of mitochondria morphology and function in HeLa cells. This study will provide novel insights into S6K1 function in mitochondria-mediated cellular signaling.

S6K1 Plays a Critical Role in Early Adipocyte Differentiation

Carnevalli, Larissa S.,Masuda, Kouhei,Frigerio, Francesca,Le Bacquer, Olivier,Um, Sung Hee,Gandin, Valentina,Topisirovic, Ivan,Sonenberg, Nahum,Thomas, George,Kozma, Sara C. Elsevier 2010 Developmental cell Vol.18 No.5

<P><B>Summary</B></P><P>Earlier, we reported that <I>S6K1</I><SUP>−/−</SUP> mice have reduced body fat mass, have elevated rates of lipolysis, have severely decreased adipocyte size, and are resistant to high fat diet (HFD)-induced obesity. Here we report that adipocytes of <I>S6K1</I><SUP>−/−</SUP> mice on a HFD have the capacity to increase in size to a degree comparable to that of wild-type (WT) mice, but not in number, indicating an unexpected lesion in adipogenesis. Tracing this lesion revealed that S6K1 is dispensable for terminal adipocyte differentiation, but is involved in the commitment of embryonic stem cells to early adipocyte progenitors. We further show that absence of S6K1 attenuates the upregulation of transcription factors critical for commitment to adipogenesis. These results led to the conclusion that a lack of S6K1 impairs the generation of de novo adipocytes when mice are challenged with a HFD, consistent with a reduction in early adipocyte progenitors.</P> <P><B>Graphical Abstract</B></P><P><ce:figure></ce:figure></P>

Ribosomal protein S6 is a selective mediator of TRAIL-apoptotic signaling

Jeon, Y-J,Kim, I K,Hong, S-H,Nan, H,Kim, H-J,Lee, H-J,Masuda, E S,Meyuhas, O,Oh, B-H,Jung, Y-K Nature Publishing Group 2008 Oncogene Vol.27 No.31

TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is a potent inducer of apoptosis in tumor cells and holds a promise as a therapeutic agent against cancer. To elucidate the death signaling evoked by TRAIL, we performed a functional genetic screening and rescued TRAIL-resistant Jurkat clones harboring ribosomal protein S6 (rpS6) cDNA in anti-sense frame. Reduction of rpS6 expression in Jurkat and HeLa cells attenuated apoptosis induced by TRAIL, but not those by other cell death signals, including tumor necrosis factor-α and cycloheximide, etoposide, doxorubicin, tunicamycin and staurosporine. Death receptor (DR) 4, but not DR5, was downregulated in rpS6 knockdown cells. Conversely, the sensitivity to TRAIL was increased by the ectopic expression of wild-type rpS6 and further by phospho-defective rpS6 mutant (S6-SS235,6AA), but not by phospho-mimic rpS6 mutant (S6-SS235,6DD). Also, unphosphorylatable rpS6 knock-in mouse embryo fibroblasts (rpS6<SUP>P−/−</SUP> MEFs) were more sensitive to TRAIL than control MEFs. In addition, SKHep-1 tumor cells, which express less phospho-rpS6 and are more sensitive to TRAIL than other tumor cells, became effectively desensitized to TRAIL after rpS6 knockdown. These results suggest that rpS6, especially in its unphosphorylated form, is a selective mediator of TRAIL-induced apoptosis.Oncogene (2008) 27, 4344–4352; doi:10.1038/onc.2008.73; published online 24 March 2008

The Results of Installation and Preliminary Test of 22.9 kV, 50 MVA, 100 m Class HTS Power Cable System at KEPCO

Sohn, S.H.,Lim, J.H.,Yim, S.W.,Hyun, O.B.,Kim, H.R.,Yatsuka, K.,Isojima, S.,Masuda, T.,Watanabe, M.,Ryoo, H.S.,Yang, H.S.,Kim, D.L.,Hwang, S.D. Institute of Electrical and Electronics Engineers 2007 IEEE transactions on applied superconductivity Vol.17 No.2

<P>As high temperature superconducting (HTS) power cables have some merits over conventional cables, several demonstration projects on the HTS cable system are presently under way around the world. Korea Electric Power Corporation (KEPCO) also initiated an HTS cable project in 2002 with the Korean government's support. A three phase 100 m HTS cable system with a capacity of 50 MVA has been installed at Gochang test yard, located in Chonnbuk province, Korea. The HTS cable system is composed of a 100 m-long cable, two terminations and a cooling system. The rated current is 1,250 A<SUB>rms</SUB> and the rated voltage is 22.9 kV considering compatibility with the conventional power distribution system in Korea. Main purposes of this project are to verify the performance of an HTS cable system and to evaluate the potential of the HTS cable system from the viewpoint of power utilities. The real grid application of the HTS cable system requires the demonstration of system reliability, accumulated operation experiences, and it has to meet the practical needs of the utilities. In such a meaning, this project provides various challenges for KEPCO, and the feedback will be delivered to cable manufacturers. This user initiative test will facilitate the introduction of HTS cable systems into a real grid network. The installation process of the HTS cable system and some results of the preliminary test were presented in this paper.</P>

Study ofπ0pair production in single-tag two-photon collisions

Masuda, M.,Uehara, S.,Watanabe, Y.,Nakazawa, H.,Abdesselam, A.,Adachi, I.,Aihara, H.,Al Said, S.,Asner, D. M.,Atmacan, H.,Aulchenko, V.,Aushev, T.,Babu, V.,Badhrees, I.,Bakich, A. M.,Barberio, E.,Behe American Physical Society 2016 Physical Review D Vol.93 No.3

<P>We report a measurement of the differential cross section of pi(0) pair production in single-tag two-photon collisions, gamma*gamma -> pi(0) pi(0), in e(+) e(-) scattering. The cross section is measured for Q(2) up to 30 GeV2, where Q(2) is the negative of the invariant mass squared of the tagged photon, in the kinematic range 0.5 GeV < W < 2.1 GeV and vertical bar cos theta*vertical bar < 1.0 for the total energy and pion scattering angle, respectively, in the gamma*gamma center-of-mass system. The results are based on a data sample of 759 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. The transition form factor of the f(0)(980) and that of the f(2)(1270) with the helicity-0, -1, and -2 components separately are measured for the first time and are compared with theoretical calculations.</P>

Study of KS0 pair production in single-tag two-photon collisions

Masuda, M.,Uehara, S.,Watanabe, Y.,Adachi, I.,Ahn, J. K.,Aihara, H.,Al Said, S.,Asner, D. M.,Atmacan, H.,Aulchenko, V.,Aushev, T.,Ayad, R.,Babu, V.,Badhrees, I.,Bansal, V.,Behera, P.,Berger, M.,Bhardw American Physical Society 2018 Physical Review D Vol.97 No.5

Iron fortification of rice seeds through activation of the nicotianamine synthase gene

Lee, S.,Jeon, U. S.,Lee, S. J.,Kim, Y.-K.,Persson, D. P.,Husted, S.,Schjorring, J. K.,Kakei, Y.,Masuda, H.,Nishizawa, N. K.,An, G. Proceedings of the National Academy of Sciences 2009 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.106 No.51

<P>The most widespread dietary problem in the world is mineral deficiency. We used the nicotianamine synthase (NAS) gene to increase mineral contents in rice grains. Nicotianamine (NA) is a chelator of metals and a key component of metal homeostasis. We isolated activation-tagged mutant lines in which expression of a rice NAS gene, OsNAS3, was increased by introducing 35S enhancer elements. Shoots and roots of the OsNAS3 activation-tagged plants (OsNAS3-D1) accumulated more Fe and Zn. Seeds from our OsNAS3-D1 plants grown on a paddy field contained elevated amounts of Fe (2.9-fold), Zn (2.2-fold), and Cu (1.7-fold). The NA level was increased 9.6-fold in OsNAS3-D1 seeds. Analysis by size exclusion chromatography coupled with inductively coupled plasma mass spectroscopy showed that WT and OsNAS3-D1 seeds contained equal amounts of Fe bound to IP6, whereas OsNAS3-D1 had 7-fold more Fe bound to a low molecular mass, which was likely NA. Furthermore, this activation led to increased tolerance to Fe and Zn deficiencies and to excess metal (Zn, Cu, and Ni) toxicities. In contrast, disruption of OsNAS3 caused an opposite phenotype. To test the bioavailability of Fe, we fed anemic mice with either engineered or WT seeds for 4 weeks and measured their concentrations of hemoglobin and hematocrit. Mice fed with engineered seeds recovered to normal levels of hemoglobin and hematocrit within 2 weeks, whereas those that ate WT seeds remained anemic. Our results suggest that an increase in bioavailable mineral content in rice grains can be achieved by enhancing NAS expression.</P>

Electrodeposition of WO₃ nanostructured thin films for electrochromic and H₂S gas sensor applications

Poongodi, S.,Kumar, Palaniswamy Suresh,Mangalaraj, D.,Ponpandian, N.,Meena, P.,Masuda, Yoshitake,Lee, Chongmu Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.719 No.-

<P><B>Abstract</B></P> <P>In this work, Vertically oriented WO<SUB>3</SUB> nanoflakes array films was synthesized via the template free facile electrodeposition method at room temperature. WO<SUB>3</SUB> nanoflakes arrays was adopted as an effective cathode electrode material in the electrochemical devices structure. The WO<SUB>3</SUB> material exhibits superior electrochromic performance shows a larger optical modulation (68.89% at 550 nm), faster response time (t<SUB>b</SUB> = 1.93 s, t<SUB>c</SUB> = 2.87 s), a higher coloration efficiency of about 154.93 cm<SUP>2</SUP> C<SUP>−1</SUP> and with excellent cyclic stability over 2000 cycles without any degradation. Futhermore, WO<SUB>3</SUB> nanoflakes array film was used for the detection of H<SUB>2</SUB>S gas that showed excellent response. A considerable increase in porosity and high surface roughness could be conducive for such an excellent and superior electrochromic characteristic as well as gas sensing performances. These results indicates that fabricated WO<SUB>3</SUB> nanoflakes array film by a simple strategy holds a great promise for potential multifunctional applications such as smart windows, gas sensors and optical sensors.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

MEASUREMENTS OF THE CORONAL ACCELERATION REGION OF A SOLAR FLARE

Krucker, Sä,m,Hudson, H. S.,Glesener, L.,White, S. M.,Masuda, S.,Wuelser, J.-P.,Lin, R. P. IOP Publishing 2010 The Astrophysical journal Vol.714 No.2

<P>The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Nobeyama Radioheliograph (NoRH) are used to investigate coronal hard X-ray and microwave emissions in the partially disk-occulted solar flare of 2007 December 31. The STEREO mission provides EUV images of the flare site at different viewing angles, establishing a two-ribbon flare geometry and occultation heights of the RHESSI and NoRH observations of similar to 16 Mm and similar to 25 Mm, respectively. Despite the occultation, intense hard X-ray emission up to similar to 80 keV occurs during the impulsive phase from a coronal source that is also seen in microwaves. The hard X-ray and microwave source during the impulsive phase is located similar to 6 Mm above thermal flare loops seen later at the soft X-ray peak time, similar in location to the above-the-loop-top source in the Masuda flare. A single non-thermal electron population with a power-law distribution (with spectral index of similar to 3.7 from similar to 16 keV up to the MeV range) radiating in both bremsstrahlung and gyrosynchrotron emission can explain the observed hard X-ray and microwave spectrum, respectively. This clearly establishes the non-thermal nature of the above-the-loop-top source. The large hard X-ray intensity requires a very large number (>5 x 10(35) above 16 keV for the derived upper limit of the ambient density of similar to 8 x 10(9) cm(-3)) of suprathermal electrons to be present in this above-the-loop-top source. This is of the same order of magnitude as the number of ambient thermal electrons. We show that collisional losses of these accelerated electrons would heat all ambient electrons to superhot temperatures (tens of keV) within seconds. Hence, the standard scenario, with hard X-rays produced by a beam comprising the tail of a dominant thermal core plasma, does not work. Instead, all electrons in the above-the-loop-top source seem to be accelerated, suggesting that the above-the-loop-top source is itself the electron acceleration region.</P>

연구발표초록 ( 재료 )

H . Maeda,S . Ikari,S . Masuda,K . Kusakabe,S . Morooka 한국화학공학회 1992 춘계학술발표회 Vol.- No.-