Functional interplay between arginyl-tRNA synthetases and arginyltransferase

Protein arginylation, mediated by arginyltransferase ATE1, is a posttranslational modification of emerging biological importance that consists of transfer of the amino acid Arg to protein and peptide substrates. ATE1 utilizes charged tRNAArg as the donor of the arginyl group, which depends on the activity of Arg-tRNA synthetases (RARS) and is also utilized in translation. The mechanisms that regulate the functional balance between ATE1, RARS and translation are unknown. Here we addressed the functional interplay between these mechanisms using intracellular arginylation sensor in cell lines with overexpression or deletion of ATE1 and RARS isoforms. We find that arginylation levels depend on the physiological state of the cells but are not directly affected by translation activity or availability of RARS isoforms. However, displacement of RARS from the multi-synthetase complex leads to an increase in intracellular arginylation independently of RARS enzymatic activity. This effect is accompanied by ATE1 redistribution into the cytosol. Our results provide the first comprehensive analysis of the interdependence between translation, arginyl-tRNA synthesis, and arginylation.

Availability of Arg, but Not tRNA, Is a Rate-Limiting Factor for Intracellular Arginylation

Protein arginylation, mediated by arginyltransferase ATE1, is a posttranslational modification of emerging biological importance that consists of transfer of the amino acid Arg from tRNA to protein and peptide targets. ATE1 can bind tRNA and exhibits specificity toward particular tRNA types, but its dependence on the availability of the major components of the arginylation reaction has never been explored. Here we investigated key intracellular factors that can potentially regulate arginylation in vivo, including several tRNA types that show strong binding to ATE1, as well as availability of free Arg, in an attempt to identify intracellular rate limiting steps for this enzyme. Our results demonstrate that, while modulation of tRNA levels in cells does not lead to any changes in intracellular arginylation efficiency, availability of free Arg is a potentially rate-limiting factor that facilitates arginylation if added to the cultured cells. Our results broadly outline global pathways that may be involved in the regulation of arginylation in vivo.

Potential benefits of Tricetin in medicine for the treatment of cancers and other health-related disorders: Medicinal importance and therapeutic benefit

Background: Medicinal plants have been used in medicine for the treatment of numerous diseases due to their medicinal properties and pharmacological activities. Popularity of herbal based drugs in the health sector has been increasing due to patient compliance and cost effectiveness. Herbal drugs derived from plant and animal source have been used in the Ayurvedic, Homeopathic, and Naturopathic system of medicine. Medicinal plants have been used as fuel, clothing, shelter and food material in worldwide since very early age. Phytoconstituents are pure plant chemicals found in different parts of the plant material. Flavonoids are important class of phytochemical found in medicinal plants and their derived products. Methods: In order to know the biological importance of tricetin, in the present investigation scientific data of tricetin in respect to their medicinal importance and pharmacological activities were collected and analyzed. Literature database such as Google, PubMed, Science Direct and Scopus has been searched using term tricetin and flavonoid. All the scientific information has been collected from these databases to know the biological importance of tricetin. Analytical data of tricetin have been also collected and analyzed in the present work to know the isolation, separation and identification procedure of trice Results: Scientific data analysis of different research work revealed the presence of tricetin in Triticum dicoccum, Lathyrus pratensis, Eucalyptus globules, Thuja occidentalis and Metasequoia glyptostroboides. Scientific data analysis signified biological importance of tricetin against different form of cancerous disorders, human osteosarcoma, glioblastoma multiforme, human breast adenocarcinoma, human non‑small cell lung cancer and liver cancer. Scientific data analysis also signified biological potential of tricetin against inflammation, neurodegenerative diseases, atherosclerosis, diabetes and respiratory syncytial virus infection. Scientific data analysis revealed the biological importance of tricetin against multidrug resistance and free radicals. Conclusions: Scientific data analysis revealed biological importance and pharmacological activities of tricetin against various form of human disorders including cancer, inflammation, neurodegeneration, atherosclerosis and diabetes.

New species of herpetofauna from the Greater Mekong region of Southeast Asia reported by WWF

A remarkable 163 new species discoveries have been made in the past year in the jungles and rivers of the Greater Mekong region of Southeast Asia. The new finds in 2008 comprise 100 plants, 28 fish, 18 reptiles, 14 amphibians, 2 mammals and 1 bird species, highlighting the biological importance of this unique and diverse land.

Drosulfakinin signaling modulates female sexual receptivity in Drosophila

Female sexual behavior as an innate behavior is of prominent biological importance for survival and reproduction. However, molecular and circuit mechanisms underlying female sexual behavior is not well understood. Here, we identify the Cholecystokinin-like peptide Drosulfakinin (DSK) promotes female sexual behavior in Drosophila. Manipulation both Dsk and DSK neuronal activity impact female sexual receptivity. In addition, we reveal that Dsk-expressing neurons receive input signal from R71G01GAL4 neurons to promote female sexual receptivity. Based on intersectional technique, we further found the regulation of female sexual behavior relies mainly on medial DSK neurons rather than lateral DSK neurons, and medial DSK neurons modulate female sexual behavior by acting on its receptor CCKLR-17D3. Thus, we characterized DSK/CCKLR-17D3 as R71G01GAL4 neurons downstream signaling to regulate female sexual behavior.

Naturalizing Aesthetics

Aesthetic processing is about what we like and dislike. It applies to all types of perceived objects, not just art works. There should be a general brain network that deals with aesthetic appraisals of like and dislike regardless of the appraised object. In order to investigate this, the authors carried out a large-scale meta-analysis of published neuroimaging studies of aesthetic processing for objects that are perceived using four different sensory pathways: vision, audition, taste, and smell. A part of the brain called the anterior insula appeared as the most concordant area of activation across the four sensory pathways. From an evolutionary standpoint, it most likely that the appreciation of human artifacts like art works piggybacked onto an existing system for the appraisal of objects of biological importance, such as food sources and potential mates.

Searching for methyllysine-binding aromatic cages

Methylation of lysine residues plays crucial roles in a wide variety of cell signaling processes. While the biological importance of recognition of methylated histones by reader domains in the cell nucleus is well established, the processes associated with methylation of non-histone proteins, particularly in the cytoplasm of the cell, are not well understood. Here, we describe a search for potential methyllysine readers using a rapid structural motif-mining algorithm Erebus, the PDB database, and knowledge of the methyllysine binding mechanisms.