EGFR tyrosine kinase regulates small-conductance Ca2+-activated K+ (hSKCa1) channels expressed in HEK-293 cells
Small conductance Ca2+-activated K+ (SKCa) channels are widely distributed in different tissues including the brain, pancreatic islets, myocardium, etc., and play an important role in controlling electrical activity and cellular functions. However, intracellular signal modulation of SKCa channels is not fully understood. The present study was designed to investigate the potential regulation of hSKCa1 channels by protein tyrosine kinases (PTKs) in HEK 293 cells expressing hSKCa1 (KCNN1) gene using approaches of whole-cell patch voltage-clamp, immunoprecipitation, Western blot, and mutagenesis. We found that hSKCa1 current w...
Source: BJ Cell - March 18, 2013 Category: Biochemistry Authors: W Wu, H Sun, X Deng, G Li Tags: BJ Signal Source Type: research
Differential regulation of glucose transport activity in yeast by specific cAMP signatures
Successful colonization and survival in variable environments require a competitive advantage during the initial growth phase after experiencing nutrient changes. Starved yeast cells anticipate exposure to glucose by activating the Hxt5p glucose transporter, which provides an advantage during early phases after glucose resupply. cAMP and glucose FRET sensors helped identifying three signaling pathways that cooperate in the anticipatory Hxt5p activity in glucose-starved cells: expectedly the Snf1 AMP kinase pathway; surprisingly, the sugar-dependent G-protein-coupled Gpr1/cAMP/PKA pathway, and the Pho85/Plc6/7 pathway. Gpr1...
Source: BJ Cell - March 15, 2013 Category: Biochemistry Authors: C Bermejo, F Haerizadeh, M S.C. Sadoine, D Chermak, W B. Frommer Tags: BJ Signal Source Type: research
MicroRNA-138 plays a role in hypoxic pulmonary vascular remodelling by targeting Mst1
Unbalanced apoptosis is a major cause of structural remodeling of vasculatures associated with pulmonary arterial hypertension (PAH), while the underlying mechanisms are still elusive. MicroRNAs (miRNAs) regulate the expression of several proteins that are important for the cell fate including differentiation, proliferation and apoptosis. It is possible that these regulatory RNA molecules play a role in the development of PAH. To test this hypothesis, we studied the effect of several miRNAs on the apoptosis of cultured pulmonary artery smooth muscle cells (PASMCs), and identified miR-138 to be an important player. The miR-...
Source: BJ Cell - March 13, 2013 Category: Biochemistry Authors: S Li, Y Ran, D Zhang, J Chen, S Li, D Zhu Tags: BJ Cell Source Type: research
TgrC1 mediates cell-cell adhesion by interacting with TgrB1 via mutual IPT/TIG domains during development of Dictyostelium discoideum
Cell-cell adhesion plays crucial roles in cell differentiation and morphogenesis during development of Dictyostelium discoideum. The heterophilic adhesion protein TgrC1 is expressed during cell aggregation and disruption of the tgrC1 gene results in the arrest of development at the loose aggregate stage. We have used far western blot coupled with mass spectrometry to identify TgrB1 as the heterophilic binding partner of TgrC1. Co-immunoprecipitation and pull-down studies showed that TgrB1 and TgrC1 are capable of binding with each other in solution. TgrB1 and TgrC1 are encoded by a pair of adjacent genes which share a comm...
Source: BJ Cell - March 12, 2013 Category: Biochemistry Authors: G Chen, J Wang, X Xu, X Wu, R Piao, C Siu Tags: BJ Cell Source Type: research
BAK activation is necessary and sufficient to drive ceramide synthase-dependent ceramide accumulation following inhibition of BCL2-like proteins
Determining mechanistic details about how drugs kill cancer cells is critical for predicting which cancers will respond to given therapeutic regimens and for identifying effective combinations of drugs that more potently kill cancer cells while sparing normal cells. The BCL2-family of proteins and bioactive sphingolipids are intricately linked during apoptotic cell death. In fact, many chemotherapeutic drugs are known to cause accumulation of the pro-apoptotic sphingolipid, ceramide, however the mechanism by which this occurs is not completely understood. Herein, we demonstrate that direct inhibition of anti-apoptotic BCL2...
Source: BJ Cell - March 12, 2013 Category: Biochemistry Authors: L J Beverly, L A Howell, M Hernandez-Corbacho, L Casson, J E Chipuk, L J Siskind Tags: BJ Cell Source Type: research
Protein disulfide isomerase interacts with soluble guanylyl cyclase via a redox-based mechanism and modulates its activity.
Nitric oxide (NO) binds to the receptor, soluble guanylyl cyclase (sGC), stimulating cGMP production. The NO-sGC-cGMP pathway is a key component in the cardiovascular system. Discrepancies in sGC activation and deactivation in vitro vs. in vivo have led to a search for endogenous factors that regulate sGC or assist in cellular localization. In our previous work, which identified Hsp70 as a modulator of sGC, we determined that protein disulfide isomerase (PDI) bound to an sGC-affinity matrix. We here establish and characterize this interaction. Incubation of purified PDI with semi-purified sGC, both reduced and oxidized, re...
Source: BJ Cell - March 11, 2013 Category: Biochemistry Authors: E J Heckler, P Crassous, P Baskaran, A Beuve Tags: BJ Signal Source Type: research
Sp sites contribute to basal and inducible expression of the human TNF{alpha}-Inducible Protein 3-Interacting Protein 1 (TNIP1) promoter
TNFα-induced protein 3-interacting protein 1 (TNIP1) is a corepressor of RAR and PPAR. Additionally, it can reduce signaling stemming from cell membrane receptors such as those for TNFα and EGF. Consequently, it influences a variety of receptor-mediated events as diverse as transcription, programmed cell death, and cell cycling. Thus, changes in TNIP1 expression levels are likely to impact multiple important biological endpoints. TNIP1 expression level changes have been linked to psoriasis and systemic sclerosis. As such, it is crucial to determine what controls its expression levels starting with constitutiv...
Source: BJ Cell - March 7, 2013 Category: Biochemistry Authors: P C Encarnacao, V P Ramirez, C Zhang, B J Aneskievich Tags: BJ Gene Source Type: research
The COUP-TFII variant lacking a DNA-binding domain inhibits the activation of the Cyp7a1 promoter through physical interaction with COUP-TFII
COUP-TFII nuclear receptor, which is composed of a DNA-binding domain and a ligand-binding domain, exerts pleiotropic effects on development and cell differentiation by regulating the transcription of its target genes, including Cyp7a1, which plays important roles in catabolism of cholesterol in liver. While there exist multiple variants of COUP-TFII, their roles in the regulation of Cyp7a1 expression have not been elucidated. In the present study, we studied the roles of the COUP-TFII-V2 (variant 2), which lacks a DNA-binding domain, in the regulation of the transcriptional control of Cyp7a1 gene by COUP-TFII in hepatocel...
Source: BJ Cell - March 5, 2013 Category: Biochemistry Authors: T Yamazaki, J Suehiro, H Miyazaki, T Minami, T Kodama, K Miyazono, T Watabe Tags: BJ Cell Source Type: research
Cooperative function and mutual stabilization of the half ATP-binding cassette transporters HAF-4 and HAF-9 in Caenorhabditis elegans
Caenorhabditis elegans HAF-4 and HAF-9 are half ABC transporters that are highly homologous to the human lysosomal peptide transporter TAPL (TAP-like; ABCB9). Previously, we reported that both HAF-4 and HAF-9 localize to the membrane of a subset of intestinal organelles, and are required for the formation of these organelles and other physiological aspects. Here, we report the genetic and physical interactions between HAF-4 and HAF-9. Overexpression of HAF-4 and HAF-9 did not rescue the intestinal organelle defect of the haf-9 and haf-4 deletion mutants, respectively, indicating that they cannot substitute for each other. ...
Source: BJ Cell - March 5, 2013 Category: Biochemistry Authors: T Tanji, K Nishikori, H Shiraishi, M Maeda, A Ohashi-Kobayashi Tags: BJ Cell Source Type: research
ADAM12 is expressed in the tumour vasculature and mediates ectodomain shedding of several membrane-anchored endothelial proteins
In conclusion, our data demonstrate a role for ADAM12 in ectodomain shedding of several membrane-anchored endothelial proteins. We speculate that this process may have importance in tumour neovascularization or/and tumour-cell extravasation. (Source: BJ Cell)
Source: BJ Cell - March 5, 2013 Category: Biochemistry Authors: C Fröhlich, M Klitgaard, J B Noer, A Kotzsch, C Nehammer, P Kronqvist, J Berthelsen, C Blobel, M Kveiborg, R Albrechtsen, U M Wewer Tags: BJ Cell Source Type: research
mRNA encoding WAVE-Arp2/3 associated proteins is co-localised with foci of active protein synthesis at the leading edge of MRC5 fibroblasts during cell migration
In this study we show that mRNAs encoding some structural and regulatory components of the WAVE complex are localised to the leading edge of the cell and associated with sites of active translation. Furthermore we demonstrate that steady state levels of ArpC2 and Rac1 proteins increase at the leading edge during cell spreading suggesting that localised protein synthesis has a pivotal role in controlling cell spreading and migration. (Source: BJ Cell)
Source: BJ Cell - March 4, 2013 Category: Biochemistry Authors: M Willett, M Brocard, H J Pollard, S J Morley Tags: BJ Cell Source Type: research
Seipin differentially regulates lipogenesis and adipogenesis through a conserved core sequence and an evolutionarily acquired C-terminus
Homozygous mutations in BSCL2/seipin cause congenital generalized lipodystrophy type 2 (CGL2). Recent data suggest that seipin regulates lipid droplet (LD) dynamics and adipocyte differentiation, but whether these roles are mechanistically linked remains unclear. To understand how seipin regulates these processes, we investigated the evolutionary changes of seipin orthologs, and studied individual domains in regulating lipid accumulation in non-adipocytes and adipocytes. Mammalian seipins comprise at least two distinct functional domains, a conserved core sequence and an evolutionarily acquired C-terminus. Despite its requ...
Source: BJ Cell - March 4, 2013 Category: Biochemistry Authors: W Yang, S Thein, X Guo, F Xu, B Venkatesh, S Sugii, G K. Radda, W Han Tags: BJ Cell Source Type: research
Characterization of a pre-export enzyme-chaperone complex on the twin-arginine transport pathway
The twin-arginine translocation (Tat) system is a protein targeting pathway utilised by prokaryotes and chloroplasts. Tat substrates are produced with distinctive N-terminal signal peptides and are translocated as fully folded proteins. In Escherichia coli Tat-dependent proteins often contain redox cofactors that must be loaded before translocation. Trimethylamine N-oxide reductase (TorA) is a model bacterial Tat substrate and is a molybdenum cofactor-dependent enzyme. Co-ordination of cofactor loading and translocation of TorA is directed by the TorD protein, which is a cytoplasmic chaperone known to physically interact w...
Source: BJ Cell - March 1, 2013 Category: Biochemistry Authors: J M Dow, F Gabel, F Sargent, T Palmer Tags: BJ Biomolecules Source Type: research
FGF-2 Prevents Cancer Cells from ER Stress-Mediated Apoptosis via Enhancing Proteasome-mediated Nck Degradation
Induction of Endoplasmic Reticulum (ER) stress-mediated apoptosis in cancer cells represents an alternative approach for cancer therapy. Whether fibroblast growth factor 2 (FGF-2)-induced survival signals may interact with ER stress signalling in cancer cells remains elusive. In this work, we showed that pretreatment with FGF-2 decreased the inhibition of DNA synthesis and induction of apoptosis by two different ER stress inducers, tunicamycin (TM) and thapsigargin (TG), in both human hepatoblastoma HepG2 cells and breast cancer MCF-7 cells. Pretreatment with FGF-2 prevented ER stress-mediated apoptosis by decreasing ER st...
Source: BJ Cell - March 1, 2013 Category: Biochemistry Authors: B Li, Z Pi, L liu, B Zhang, X Huang, P Hu, E Chevet, P Yi, J Liu Tags: BJ Signal Source Type: research
Characterisation of a pre-export enzyme-chaperone complex on the twin-arginine transport pathway
The twin-arginine translocation (Tat) system is a protein targeting pathway utilised by prokaryotes and chloroplasts. Tat substrates are produced with distinctive N-terminal signal peptides and are translocated as fully folded proteins. In Escherichia coli Tat-dependent proteins often contain redox cofactors that must be loaded before translocation. Trimethylamine N-oxide reductase (TorA) is a model bacterial Tat substrate and is a molybdenum cofactor-dependent enzyme. Co-ordination of cofactor loading and translocation of TorA is directed by the TorD protein, which is a cytoplasmic chaperone known to physically interact w...
Source: BJ Cell - March 1, 2013 Category: Biochemistry Authors: J M Dow, F Gabel, F Sargent, T Palmer Tags: BJ Structure Source Type: research
