Lysine-specific demethylase 1 (LSD1) was recently identified as the first histone demethylase that specifically demethylates monomethylated and dimethylated histone H3 at K4. It is a component of the CoREST and other corepressor complexes and plays an important role in silencing neuronal-specific genes in nonneuronal cells, but the molecular mechanisms of its action remain unclear. The 2.8-Å-resolution crystal structure of the human LSD1 reveals that LSD1 defines a new subfamily of FAD-dependent oxidases. The active center of LSD1 is characterized by a remarkable 1,245-Å 3 substrate-binding cavity with a highly negative electrostatic potential. Although the protein core of LSD1 resembles other flavoenzymes, its enzymatic activity and functions require two additional structural modules: an N-terminal SWIRM domain important for protein stability and a large insertion in the catalytic domain indispensable both for the demethylase activity and the interaction with CoREST. These results provide a framework for further probing the catalytic mechanism and the functional roles of LSD1.histone modification ͉ flavoenzyme ͉ catalysis H istone proteins are subject to a variety of posttranslational modifications, including acetylation, methylation, phosphorylation, and ubiquitination, and it is these histone modifications that function as the molecular switches that alter the state of compaction of chromatin to allow gene activation or repression (1-3). Some histone modifications (e.g., acetylation and phosphorylation) are highly dynamic, whereas others (e.g., methylation) have been regarded as ''permanent'' chromatin marks. However, the discoveries of lysine-specific demethylase 1 (LSD1) and jumonji domain C (JmjC) domain-containing histone demethylase 1 (JHDM1) have changed this picture (4, 5). Shi and colleagues demonstrated that LSD1 is a histone lysine demethylase that specifically demethylates monomethylated and dimethylated histone H3 at K4 (4). More recently, we and others have shown that many JmjC domaincontaining proteins are capable of demethylating dimethylated and trimethylated histone proteins (4-10). These findings suggest that histone methylation is a reversible modification and can be regulated under similar enzymatic control as other histone modifications (11-13).LSD1 is a component of a number of transcriptional corepressor complexes, such as CoREST, CtBP, and HDAC complexes, and plays an important role in silencing neuronal-specific genes in nonneuronal cells (14-19). The C-terminal two-thirds of LSD1 contains an amine oxidase-like (AOL) domain, which shares extensive sequence homology to FAD-dependent oxidases ( Fig. 1 A and C) (20-22). In addition, LSD1 also contains an N-terminal SWIRM domain (Fig. 1 A), which has been recently identified as a conserved motif often found in chromatin remodeling and modifying complexes with unknown function (23). Recent studies suggest that the specificity and activity of LSD1 can be modulated by its interacting factors (4, 24-26). However, the molecular mechanism by w...

High insulin/IGF is a biologic link between diabetes and cancers, but the underlying molecular mechanism remains unclear. Here we report a previously unrecognized tumour-promoting mechanism for stress protein TRB3, which mediates a reciprocal antagonism between autophagic and proteasomal degradation systems and connects insulin/IGF to malignant promotion. We find that several human cancers express higher TRB3 and phosphorylated insulin receptor substrate 1, which correlates negatively with patient's prognosis. TRB3 depletion protects against tumour-promoting actions of insulin/IGF and attenuates tumour initiation, growth and metastasis in mice. TRB3 interacts with autophagic receptor p62 and hinders p62 binding to LC3 and ubiquitinated substrates, which causes p62 deposition and suppresses autophagic/proteasomal degradation. Several tumour-promoting factors accumulate in cancer cells to support tumour metabolism, proliferation, invasion and metastasis. Interrupting TRB3/p62 interaction produces potent antitumour efficacies against tumour growth and metastasis. Our study opens possibility of targeting this interaction as a potential novel strategy against cancers with diabetes.

CABI:20153174020Understanding how plants are constructed - i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals - is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to different environments. While a variety of models dealing with biomass allocation exist, we lack a synthetic understanding of the underlying processes. This is partly due to the lack of suitable data sets for validating and parameterizing models. To that end, we present the Biomass And Allometry Database (BAAD) for woody plants. The BAAD contains 259634 measurements collected in 176 different studies, from 21084 individuals across 678 species. Most of these data come from existing publications. However, raw data were rarely made public at the time of publication. Thus, the BAAD contains data from different studies, transformed into standard units and variable names. The transformations were achieved using a common workflow for all raw data files. Other features that distinguish the BAAD are: (i) measurements were for individual plants rather than stand averages; (ii) individuals spanning a range of sizes were measured; (iii) plants from 0.01-100 m in height were included; and (iv) biomass was estimated directly, i.e., not indirectly via allometric equations (except in very large trees where biomass was estimated from detailed sub-sampling). We included both wild and artificially grown plants. The data set contains the following size metrics: total leaf area; area of stem cross-section including sapwood, heartwood, and bark; height of plant and crown base, crown area, and surface area; and the dry mass of leaf, stem, branches, sapwood, heartwood, bark, coarse roots, and fine root tissues. We also report other properties of individuals (age, leaf size, leaf mass per area, wood density, nitrogen content of leaves and wood), as well as information about the growing environment (location, light, experimental treatment, vegetation type) where available. It is our hope that making these data available will improve our ability to understand plant growth, ecosystem dynamics, and carbon cycling in the world's vegetation

Understanding the mechanism of radioresistance could help develop strategies to improve therapeutic response of patients with PDAC. The gene is frequently mutated in pancreatic cancer. In this study, we investigated the role of deficiency in pancreatic cancer cells' response to radiotherapy. We downregulated SMAD4 expression with siRNA or shRNA and overexpressed SMAD4 in mutant pancreatic cancer cells followed by clonogenic survival assay to evaluate their effects on cell radioresistance. To study the mechanism of radioresistance, the effects of loss on reactive oxygen species (ROS) and autophagy were determined by flow cytometry and immunoblot analysis, respectively. Furthermore, we measured radioresistance by clonogenic survival assay after treatment with autophagy inhibitor (Chloroquine) and ROS inhibitor (N-acetyl-l-cysteine) in -depleted pancreatic cancer cells. Finally, the effects of on radioresistance were also confirmed in an orthotopic tumor model derived from -depleted Panc-1 cells.-depleted pancreatic cancer cells were more resistant to radiotherapy based on clonogenic survival assay. Overexpression of wild-type SMAD4 in -mutant cells rescued their radiosensitivity. Radioresistance mediated by depletion was associated with persistently higher levels of ROS and radiation-induced autophagy. Finally, depletion induced radioresistance in Panc-1-derived orthotopic tumor model ( = 0.038). More interestingly, we observed that the protein level of SMAD4 is inversely correlated with autophagy in orthotopic tumor tissue samples. Our results demonstrate that defective is responsible for radioresistance in pancreatic cancer through induction of ROS and increased level of radiation-induced autophagy..