PDGF-mediated autophagy regulates vascular smooth muscle cell phenotype and resistance to oxidative stress
Vascular injury and chronic arterial diseases result in exposure of vascular smooth muscle cells (VSMCs) to increased concentrations of growth factors. The mechanisms by which growth factors trigger VSMC phenotype transitions remain unclear. Because cellular reprogramming initiated by growth factors requires not only the induction of genes involved in cell proliferation but also the removal of contractile proteins, we hypothesized that autophagy is an essential modulator of VSMC phenotype. Treatment of VSMCs with platelet-derived growth factor (PDGF)-BB resulted in decreased expression of the contractile phenotype markers ...
Source: BJ Cell - February 20, 2013 Category: Biochemistry Authors: J K Salabei, T D. Cummins, M Singh, S P Jones, A Bhatnagar, B G Hill Tags: BJ Disease Source Type: research
Mapping of interactions between the amino and carboxy termini and the channel core in hERG K{+} channels
In this report, we analyzed by a site-directed cysteine and disulfide chemistry approach whether the eag/PAS and proximal domains at the hERG amino terminus exert a role in controlling the access of the N-terminal flexible tail to its binding site in the channel core for interaction with the gating machinery. Whereas the eag/PAS domain is necessary for disulfide bridging the cysteines introduced at positions 3 and 542 of the hERG sequence, the presence of the proximal domain seems to be dispensable. The state-dependent formation of a disulfide bridge between cysteine at position 3 and an endogenous cysteine located at posi...
Source: BJ Cell - February 18, 2013 Category: Biochemistry Authors: P de la Peña, A Machín, J Fernández-Trillo, P Dominguez, F Barros Tags: BJ Cell Source Type: research
Protein recognition of the S23906-1{-}DNA adduct by nuclear proteins: direct involvement of glyceraldehyde-3-phosphate-dehydrogenase (GAPDH)
The objective of this study is to identify proteins involved in the recognition and mechanism of action of S23906-DNA adducts. We found glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) as a protein that binds to S23906-alkylated single-, double-stranded and telomeric sequences in a drug-dependant and DNA sequence/structure-dependant manner. We used cyclic amplification of sequence targeting (CASTing) method to identify GAPDH DNA-binding selectivity and then evaluate its binding to such selected S23906-alkylated sequences. At the cellular level, alkylation of S23906-1 results in an increase of the binding of GAPDH and its p...
Source: BJ Cell - February 14, 2013 Category: Biochemistry Authors: G Lenglet, S Depauw, D Mendy, M David-Cordonnier Tags: BJ Cell Source Type: research
Protein recognition of the S23906-1/DNA adduct by nuclear proteins: Direct involvement of glyceraldehyde-3-phosphate-dehydrogenase (GAPDH)
The objective of this study is to identify proteins involved in the recognition and mechanism of action of S23906-DNA adducts. We found glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) as a protein that binds to S23906-alkylated single-, double-stranded and telomeric sequences in a drug-dependant and DNA sequence/structure-dependant manner. We used cyclic amplification of sequence targeting (CASTing) method to identify GAPDH DNA-binding selectivity and then evaluate its binding to such selected S23906-alkylated sequences. At the cellular level, alkylation of S23906-1 results in an increase of the binding of GAPDH and its p...
Source: BJ Cell - February 14, 2013 Category: Biochemistry Authors: G Lenglet, S Depauw, D Mendy, M David-Cordonnier Tags: BJ Cell Source Type: research
Deleted in Breast Cancer-1 (DBC1) modulates the stability and function of the nuclear receptor Rev-erb{alpha}
The nuclear receptor Rev-erbα has been implicated as a major regulator of the circadian clock and integrates circadian rhythm and metabolism. Rev-erbα controls circadian oscillations of several clock genes and Rev-erbα protein degradation is important for maintenance of the circadian oscillations and also for adipocyte differentiation. Elucidating the mechanisms that regulates Rev-erbα stability is essential for our understanding of these processes. Here we report that the protein Deleted in Breast Cancer 1 (DBC1) is a novel regulator of Rev-erbα. Rev-erbα and DBC1 interact in cell...
Source: BJ Cell - February 12, 2013 Category: Biochemistry Authors: C CS Chini, C Escande, V Nin, E N Chini Tags: BJ Cell Source Type: research
The P-body component USP52/PAN2 is a novel regulator of HIF1A mRNA stability
Hypoxia Inducible Factor-1 alpha (HIF1A) is the master regulator of the cellular response to hypoxia and is implicated in cancer progression. While the regulation of HIF1A protein in response to oxygen is well characterized, less is known about the fate of HIF1A mRNA. Here, we have identified the pseudoDUB/deadenylase USP52/PAN2 as an important regulator of the HIF1A-mediated hypoxic response. Depletion of USP52 reduced HIF1A mRNA and protein levels and resulted in reduced expression of HIF1A-regulated hypoxic targets due to a 3’UTR-dependent, polyA-tail length-independent destabilization in HIF1A mRNA. Mass spectro...
Source: BJ Cell - February 11, 2013 Category: Biochemistry Authors: J S Bett, A F.M. Ibrahim, A K Garg, V Kelly, P Pedrioli, S Rocha, R T. Hay Tags: BJ Cell Source Type: research
Prohepcidin Binds to the HAMP Promoter and Autoregulates its Own Expression
In this study, we propose a novel role for prohepcidin in the regulation of its own transcription. Using indirect immunofluorescence and mCherry tagging, a portion of prohepcidin was detected in the nucleus of hepatocytes. Prohepcidin was found to specifically bind to the STAT3 site in the promoter of HAMP. Overexpression of prohepcidin in WRL68 cells decreased HAMP promoter activity, whereas decreasing the amount of prohepcidin caused increased promoter activity measured by luciferase reporter-gene assay. Moreover, overexpression of the known prohepcidin binding partner, alpha-1 antitrypsin caused increased HAMP promoter ...
Source: BJ Cell - February 7, 2013 Category: Biochemistry Authors: E Pandur, K Sipos, L Grama, J Nagy, V S Poór, G Sétáló Jr., A Miseta, Z Fekete Tags: BJ Cell Source Type: research
HSP90 Inhibitors Enhance Differentiation and Microphthalmia Transcription Factor (MITF) Activity in Osteoclast Progenitors
The HSP90 inhibitor, 17-allylamino-demethoxygeldanamycin (17-AAG) increases osteoclast formation both in vitro and in vivo, an action that can enhance cancer invasion and growth in the bone microenvironment. The cellular mechanisms through which 17-AAG exerts this action are not understood. Thus, we sought to clarify 17-AAG actions on osteoclasts and determine whether other HSP90 inhibitors had similar properties. We determined that 17-AAG and structurally unrelated HSP90 inhibitors CCT018159 and NVP-AUY922 dose dependently increased RANKL-stimulated osteoclastogenesis in mouse bone marrow and pre-osteoclastic RAW264.7 cel...
Source: BJ Cell - February 5, 2013 Category: Biochemistry Authors: A J van der Kraan, R C C Chai, P P Singh, B J Lang, J Xu, M T Gillespie, J T Price, J M W Quinn Tags: BJ Cell Source Type: research
Zinc-Dependent Lysosomal Enlargement in TRPML1-Deficient Cells Involves MTF-1 Transcription Factor and ZnT4 (Slc30a4) Transporter
Zn is critical for a multitude of cellular processes, including gene expression, secretion and enzymatic activities. Cellular Zn is controlled by Zn-chelating proteins and by Zn transporters. The recent identification of Zn permeability of the lysosomal ion channel TRPML1, and the evidence of abnormal Zn levels in cells deficient in TRPML1, suggested a role for TRPML1 in Zn transport. Here we provide new evidence for such a role and identify additional cellular components responsible for it. In agreement with the previously published data, an acute siRNA-driven TRPML1 knockdown (KD) leads to the buildup of large cytoplasmi...
Source: BJ Cell - February 1, 2013 Category: Biochemistry Authors: I Kukic, J Kuo Lee, J Renee Coblentz, S L Kelleher, K Kiselyov Tags: BJ Cell Source Type: research
Interaction of NuMA protein with the kinesin Eg5: its possible role in bipolar spindle assembly and chromosome alignment
Bipolar spindle assembly in mitotic cells is a prerequisite to ensure correct alignment of chromosomes for their segregation to each daughter cell; spindle microtubules are tethered at plus ends to chromosomes and focused at minus ends to ether of the two spindle poles. The nuclear mitotic apparatus protein (NuMA) is present solely in the nucleus in interphase cells, but relocalizes during mitosis to the spindle poles to play a crucial role in spindle assembly via focusing spindle microtubules to each pole. Here we show that the kinesin-5 family motor Eg5 is a protein that directly interacts with NuMA, using a proteomics a...
Source: BJ Cell - February 1, 2013 Category: Biochemistry Authors: Y Iwakiri, S Kamakura, J Hayase, H Sumimoto Tags: BJ Cell Source Type: research
Eukaryotic Initiation Factor 5A Dephosphorylation is Required for Translational Arrest in Stationary Phase Cells
The protein known as eukaryotic initiation factor 5A (eIF5A) has an elusive role in translation. It has a unique and essential hypusine modification in a conserved lysine residue in most eukaryotes. In addition, this protein is modified by phosphorylation with unknown functions. Here we show that a phosphorylated state of eIF5A predominates in exponentially growing Trypanosoma cruzi cells and extensive dephosphorylation occurs in cells in stationary phase. Phosphorylation occurs mainly at Ser 2, as shown in yeast eIF5A. In addition, a novel phosphorylation site was identified at Tyr 21. In exponential cells, T. cruzi eIF5A...
Source: BJ Cell - January 31, 2013 Category: Biochemistry Authors: J Chung, A Augusto Rocha, R Rosito Tonelli, B Amaral Castilho, S Schenkman Tags: BJ Signal Source Type: research
Phosphorylation regulates TRPV1 association with {beta}-arrestin-2
In this study, we demonstrate that phosphorylation of TRPV1 and β-arrestin-2 regulates this association at the membrane. Under serum-free media conditions, we observed a significant decrease in TRPV1 and β-arrestin-2 association in transfected CHO cells. Pharmacological activation of kinases PKA and PKC led to a robust increase in TRPV1 and β-arrestin-2 association, while inhibition of PKA and PKC decreased association. Previously, we identified potential PKA residues (S116, T370) in the N-terminus of TRPV1 modulated by β-arrestin-2. In this study we reveal that the phosphorylation status of T37...
Source: BJ Cell - January 30, 2013 Category: Biochemistry Authors: E D. Por, R Gomez, A N. Akopian, N A. Jeske Tags: BJ Cell Source Type: research
Regulation of Bacillus subtilis DesK Thermosensor by Lipids
Temperature sensing is essential for the survival of living cells. The membrane-bound thermosensor DesK from Bacillus subtilis is a key representative of histidine kinases receptors suited to remodel membrane lipid composition when the temperature drops below ~30ºC. Although the receptor is well studied, a central issue remains: How does the compositional and functional diversity of the surrounding membrane modulate receptor function?. Reconstituting full-length DesK into proteoliposomes of well-defined and controlled lipid composition represents a minimal synthetic approach to systematically address this question. ...
Source: BJ Cell - January 29, 2013 Category: Biochemistry Authors: M Martín, D de Mendoza Tags: BJ Signal Source Type: research
The mannose 6-phosphate binding sites of M6P/IGF2R determine its capacity to suppress matrix invasion by squamous cell carcinoma cells
The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) interacts with a variety of factors that impinge on tumour invasion and metastasis. It has been shown that expression of wild-type M6P/IGF2R reduces the tumourigenic and invasive properties of receptor-deficient SCC-VII squamous cell carcinoma cells. We have now used mutant forms of M6P/IGF2R to assess the relevance of the different ligand-binding sites of the receptor for its biological activities in this cellular system. Our results demonstrate that M6P/IGF2R does not require a functional binding site for insulin-like growth factor II for inhibiti...
Source: BJ Cell - January 25, 2013 Category: Biochemistry Authors: O C. Probst, E Karayel, N Schida, E Nimmerfall, E Hehenberger, V Puxbaum, L Mach Tags: BJ Cell Source Type: research
ICAT is a novel PTF1A interactor that regulates pancreatic acinar differentiation and displays altered expression in tumors
The Pancreas Transcription Factor 1 (PTF1) complex is a master regulator of differentiation of acinar cells, responsible for the production of digestive enzymes. In the adult pancreas, PTF1 contains two pancreas-restricted transcription factors: Ptf1a and Rbpjl. PTF1 recruits P/CAF which acetylates Ptf1a and enhances its transcriptional activity. Using a yeast two hybrid screening, we identified ICAT (Inhibitor of ß-Catenin and Tcf4) as a novel Ptf1a interactor. ICAT regulates the Wnt pathway and cell proliferation. We validated and mapped the ICAT-Ptf1a interaction in vitro and in vivo. We demonstrated that - upon ...
Source: BJ Cell - January 22, 2013 Category: Biochemistry Authors: M Luisa Campos, V Sánchez-Arévalo Lobo, A Rodolosse, C J. Gottardi, A Mafficini, S Beghelli, M Scardoni, C Bassi, A Scarpa, F X Real Tags: BJ Disease Source Type: research
