Antagonistic Effect of a Cytoplasmic Domain on the Basal Activity of Polymodal Potassium Channels

TREK/TRAAK channels are polymodal K+ channels that convert very diverse stimuli, including bioactive lipids, mechanical stretch and temperature, into electrical signals. The nature of the structural changes that regulate their activity remains an open question. Here, we show that a cytoplasmic domain (the proximal C-ter domain, pCt) exerts antagonistic effects in TREK1 and TRAAK. In basal conditions, pCt favors activity in TREK1 whereas it impairs TRAAK activity. Using the conformation-dependent binding of fluoxetine, we show that TREK1 and TRAAK conformations at rest are different, and under the influence of pCt. Finally, we show that depleting PIP2 in live cells has a more pronounced inhibitory effect on TREK1 than on TRAAK. This differential regulation of TREK1 and TRAAK is related to a previously unrecognized PIP2-binding site (R329, R330, and R331) present within TREK1 pCt, but not in TRAAK pCt. Collectively, these new data point out pCt as a major regulatory domain of these channels and suggest that the binding of PIP2 to the pCt of TREK1 results in the stabilization of the conductive conformation in basal conditions

Spinal Cord Injury Markedly Altered Protein Expression Patterns in the Affected Rat Urinary Bladder during Healing Stages

The influence of spinal cord injury (SCI) on protein expression in the rat urinary bladder was assessed by proteomic analysis at different time intervals post-injury. After contusion SCI between T9 and T10, bladder tissues were processed by 2-DE and MALDI-TOF/MS at 6 hr to 28 days after SCI to identify proteins involved in the healing process of SCI-induced neurogenic bladder. Approximately 1,000 spots from the bladder of SCI and sham groups were visualized and identified. At one day after SCI, the expression levels of three protein were increased, and seven spots were down-regulated, including heat shock protein 27 (Hsp27) and heat shock protein 20 (Hsp20). Fifteen spots such as S100-A11 were differentially expressed seven days post-injury, and seven proteins including transgelin had altered expression patterns 28 days after injury. Of the proteins with altered expression levels, transgelin, S100-A11, Hsp27 and Hsp20 were continuously and variably expressed throughout the entire post-SCI recovery of the bladder. The identified proteins at each time point belong to eight functional categories. The altered expression patterns identified by 2-DE of transgelin and S100-A11 were verified by Western blot. Transgelin and protein S100-A11 may be candidates for protein biomarkers in the bladder healing process after SCI

Gateway RFP-fusion vectors for high-throughput functional analysis of genes

There is an increasing demand for high throughput (HTP) methods for gene analysis on a genome-wide scale. However, the current repertoire of HTP detection methodologies allows only a limited range of cellular phenotypes to be studied. We have constructed two HTP-optimized expression vectors generated from the red fluorescent reporter protein (RFP) gene. These vectors produce RFP-tagged target proteins in a multiple expression system using gateway cloning technology (GCT). The RFP tag was fused with the cloned genes, thereby allowing us localize the expressed proteins in mammalian cells. The effectiveness of the vectors was evaluated using an HTP-screening system. Sixty representative human C2 domains were tagged with RFP and overexpressed in HiB5 neuronal progenitor cells, and we studied in detail two C2 domains that promoted the neuronal differentiation of HiB5 cells. Our results show that the two vectors developed in this study are useful for functional gene analysis using an HTP-screening system on a genome-wide scale.We appreciate the helpful advice of Dr. Tobias Meyer and Dr. Won Do Heo of Stanford University in the construction of the set of entry clones of human C2 domains. This work was supported by a grant from the Basic Research Program of the Korea Science and Engineering Foundation (R01-2002- 000-00128-0), and a Korea Research Foundation Grant (KRF- 2006-005-J04204)

Physicochemical Properties, Biological Activity, Health Benefits, and General Limitations of Aged Black Garlic: A Review

Garlic (Allium sativum) has been used as a medicinal food since ancient times. However, some people are reluctant to ingest raw garlic due to its unpleasant odor and taste. Therefore, many types of garlic preparations have been developed to reduce these attributes without losing biological functions. Aged black garlic (ABG) is a garlic preparation with a sweet and sour taste and no strong odor. It has recently been introduced to Asian markets as a functional food. Extensive in vitro and in vivo studies have demonstrated that ABG has a variety of biological functions such as antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-allergic, cardioprotective, and hepatoprotective effects. Recent studies have compared the biological activity and function of ABG to those of raw garlic. ABG shows lower anti-inflammatory, anti-coagulation, immunomodulatory, and anti-allergic effects compared to raw garlic. This paper reviews the physicochemical properties, biological activity, health benefits, adverse effects, and general limitations of ABG

Gtensor: Fast and Accurate Tensor Analysis System using GPUs

© 2020 ACM.Given a large tensor, how can we analyze it efficiently? Multi-dimensional arrays or tensors have been widely used to model real-world data. Tensor decomposition plays an important role in analyzing trends and major factors in tensors. While several tensor analysis tools have been developed, they show slow running time and limited scalability due to their heavy computational requirements. In this paper, we propose Gtensor, a fast and accurate tensor mining library using GPUs. Gtensor is carefully designed to utilize GPUs in addition to CPUs for fast analysis of tensors. Gtensor provides versatile tensor algebra tools including tensor decomposition, tensor generation, tensor-tensor operation, and tensor manipulation. We invite our audience to interact with Gtensor and analyze real-world tensor data in the domains of movie recommendation, place recommendations, and academic citation.N

Accurate Online Tensor Factorization for Temporal Tensor Streams with Missing Values

© 2021 ACM.Given a time-evolving tensor stream with missing values, how can we accurately discover latent factors in an online manner to predict missing values? Online tensor factorization is a crucial task with many important applications including the analysis of climate, network traffic, and epidemic disease. However, existing online methods have disregarded temporal locality and thus have limited accuracy. In this paper, we propose STF (Streaming Tensor Factorization), an accurate online tensor factorization method for real-world temporal tensor streams with missing values. We exploit an attention-based temporal regularization to learn inherent temporal patterns of the streams. We also propose an efficient online learning algorithm which allows each row of the temporal factor matrix to be updated from past and future information. Extensive experiments show that the proposed method gives the state-of-the-art accuracy, and quickly processes each tensor slice.N