Dong-Min Kang

The checkpoint protein Chfr delays entry into mitosis, in the presence of mitotic stress (Scolnick, D.M., and T.D. Halazonetis. 2000. Nature. 406:430-435). We show here that Chfr is a ubiquitin ligase, both in vitro and in vivo. When transfected into HEK293T cells, Myc-Chfr promotes the formation of high molecular weight ubiquitin conjugates. The ring finger domain in Chfr is required for the ligase activity; this domain auto-ubiquitinates, and mutations of conserved residues in this domain abol

Hydrogen peroxide (H2O2) is an oxidizing agent that induces cellular damage at inappropriate concentrations and gives rise to an arrest during cell cycle progression, causing cell death. Recent evidence indicates that H2O2 also acts as a promoter for cell cycle progression by oxidizing specific thiol proteins. The intracellular concentration of H2O2 is regulated tightly, enabling its use as a cellular signaling molecule while minimizing its potential to cause cellular damage. Peroxiredoxins (Prx

A new chromogenic chemosensor based on lysine-functionalized silver nanoparticles 1 was prepared and characterized by transmission electron microscopy (TEM), Fourier transform Raman, and ultraviolet-visible (UV-vis) spectroscopy. The color changes of nanoparticles 1 in the absence and the presence of metal ion were observed upon addition of various amino acids and proteins in aqueous solution. Among the various amino acids, the sensor 1 in the absence of metal ion shows a novel colorimetric sens

Signaling by the hedgehog (hh)-class gene pathway is essential for embryogenesis in organisms ranging from Drosophila to human. We have isolated a hh homolog (Hro-hh) from a lophotrochozoan species, the glossiphoniid leech, Helobdella robusta, and examined its expression by reverse transcription polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization. The peak of Hro-hh expression occurs during organogenesis (stages 10-11). No patterned expression was detected within the segment

As an intracellular degradation system, autophagy is an essential and defensive cellular program required for cell survival and cellular metabolic homeostasis in response to various stresses, such as nutrient deprivation and the accumulation of damaged organelles. In general, autophagy flux consists of four steps: (1) initiation (formation of phagophore), (2) maturation and completion of autophagosome, (3) fusion of autophagosomes with lysosomes (formation of autolysosome), and (4) degradation o

Abstract Fluorescein‐functionalized silica nanoparticles ( 1 ) were prepared by sol–gel reaction, and their optical sensing abilities were studied towards finding a new type of synthetic fluorogenic chemosensor for imaging Cu 2+ ions in living cells. Interestingly, upon addition of Cu 2+ in a H 2 O suspension of 1 at pH 7.4, 1 displays large chelation‐enhanced quenching (CHEQ) effects with Cu 2+ . With the exception of Cu 2+ , no significant fluorescence intensity changes were observed in the ex

To more accurately assess the pathways of biological systems, a probe is needed that may respond selectively to adenosine triphosphate (ATP) for both in vitro and in vivo detection modes. We have developed a luminescence probe that can provide real-time information on the extent of ATP, ADP, and AMP by virtue of the luminescence and luminescence lifetime observed from a supramolecular polymer based on a C 3 symmetrical terpyridine complex with Tb 3+ ( S1-Tb ). The probe shows remarkable selectiv

A new fluoro-chromogenic chemosensor based on BODIPY-functionalized gold nanoparticles 1 is prepared. Addition of Cu(2+) ions to aqueous solutions of 1 gave an instantaneous color change along with a blue-shift of the absorption band and quenching of the emission spectrum at room temperature. The chemosensor 1 exhibits a high affinity and selectivity for Cu(2+) over competing metal ions tested. Moreover, confocal microscopy experiments establish that 1 can be used for detecting Cu(2+) levels wit

The chemical instability of line patterned Ge2Sb2Te5 was studied by transmission electron microscopy after electrically inducing melt and solidification. Compositional analysis showed elemental separation of Te to the anode side, while Ge and Sb mutually separated at the cathode side. Such elemental separation of Ge2Sb2Te5 is explained by the electric field effects and thermodynamic driving forces.

The zinc tank: A new fluoro-chromogenic chemosensor based on BODIPY-functionalized Fe(3)O(4) nanoparticles (1) has been prepared. Chemoprobe 1 exhibits high selectivity for Zn(2+) over other competing metal ions tested. Moreover, confocal microscopy experiments established that 1 can be used for detecting Zn(2+) levels in living cells (see figure).

Diclofenac, a nonsteroidal anti-inflammatory drug (NSAID) used to treat inflammatory diseases induces cellular toxicity by increasing the production of reactive oxygen species (ROS) and impairing autophagic flux. In this study, we investigated whether diclofenac induces cancer cell death and the mechanism by which diclofenac causes cell death. We observed that diclofenac induces mitotic arrest with a half-maximal effective concentration of 170 μM and cell death with a half-maximal lethal dose of

The serine/threonine kinase AKT is a major effector during phosphatidylinositol 3-kinase (PI3K)-driven cell signal transduction in response to extracellular stimuli. AKT activation mechanisms have been extensively studied; however, the mechanism underlying target of rapamycin complex 2 (mTORC2) phosphorylation of AKT at Ser473 in the cellular endomembrane system remains to be elucidated. Here, we demonstrate that endocytosis is required for AKT activation through phosphorylation at Ser473 via mT

Summay Based on the structure of limipterin (Cha, Pfleiderer, and Yim, Helv, Chim. Acta, 78: 600-614. 1995 the biosynthetic pathway for the newly identified pterin glycoside was investigated. It was demonstrated that tetrahydrolimipterin (H 4 -limipterin) can be synthesized from GTP by the enzymes GTP cyclohydrolase I, 6-pyruvoyltetrahydropterin (PTP) synthase, sepiaptcrin reductase and limipterin synthase, present in the extract of Chlorobium limicola. Limipterin synthase (UDP-N -acetylglucosam