Enhanced Formation of Scrapie Prion Protein in Cultured Cells by Treatment with Mycosporine-like Amino Acids(MAAs)

2015 ◽  
Vol 43 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Jihyun Lee ◽  
Sang-Hyun Moh ◽  
Chongsuk Ryou ◽  
Dae-Hwan Kim
Keyword(s):  
Amino Acids ◽  
Prion Protein ◽  
Cultured Cells

scholarly journals The Cellular Prion Protein Prevents Copper-Induced Inhibition of P2X4Receptors

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Ramón A. Lorca ◽  
Lorena Varela-Nallar ◽  
Nibaldo C. Inestrosa ◽  
J. Pablo Huidobro-Toro
Keyword(s):  
Amino Acids ◽  
Synaptic Transmission ◽  
Prion Protein ◽  
Adenosine Triphosphate ◽  
Response Curve ◽  
Physiological Function ◽  
Cellular Prion Protein ◽  
Synaptic Activity ◽  
Receptor Subtype ◽  
Concentration Response Curve

Although the physiological function of the cellular prion protein (PrPC) remains unknown, several evidences support the notion of its role in copper homeostasis. PrPCbinds Cu2+through a domain composed by four to five repeats of eight amino acids. Previously, we have shown that the perfusion of this domain prevents and reverses the inhibition by Cu2+of the adenosine triphosphate (ATP)-evoked currents in the P2X4receptor subtype, highlighting a modulatory role for PrPCin synaptic transmission through regulation of Cu2+levels. Here, we study the effect of full-length PrPCin Cu2+inhibition of P2X4receptor when both are coexpressed. PrPCexpression does not significantly change the ATP concentration-response curve in oocytes expressing P2X4receptors. However, the presence of PrPCreduces the inhibition by Cu2+of the ATP-elicited currents in these oocytes, confirming our previous observations with the Cu2+binding domain. Thus, our observations suggest a role for PrPCin modulating synaptic activity through binding of extracellular Cu2+.

scholarly journals The prion protein family member Shadoo induces spontaneous ionic currents in cultured cells

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Antal Nyeste ◽  
Claudia Stincardini ◽  
Petra Bencsura ◽  
Milica Cerovic ◽  
Emiliano Biasini ◽  
...  
Keyword(s):  
Family Member ◽  
Prion Protein ◽  
Cultured Cells ◽  
Ionic Currents ◽  
Protein Family

Prion protein protects against DNA damage induced by paraquat in cultured cells

2004 ◽  
Vol 37 (8) ◽  
pp. 1224-1230 ◽  
Author(s):  
Abderrahmane Senator ◽  
Walid Rachidi ◽  
Sylvain Lehmann ◽  
Alain Favier ◽  
Mustapha Benboubetra
Keyword(s):  
Dna Damage ◽  
Prion Protein ◽  
Cultured Cells

scholarly journals The Charge Structure of Helix 1 in the Prion Protein Regulates Conversion to Pathogenic PrPSc

2006 ◽  
Vol 80 (17) ◽  
pp. 8521-8529 ◽  
Author(s):  
Eric M. Norstrom ◽  
James A. Mastrianni
Keyword(s):  
Amino Acids ◽  
Prion Protein ◽  
Prion Diseases ◽  
Alpha Helix ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Salt Bridges ◽  
Subsequent Work ◽  
Complete Reversal ◽  
Terminal Amino

ABSTRACT The prion diseases are transmissible neurodegenerative disorders linked to a pathogenic conformer (PrPSc) of the normal prion protein (PrPC). Accumulation of PrPSc occurs via a poorly defined process in which PrPSc complexes with and converts endogenous PrPC to nascent PrPSc. Recent experiments have focused on the highly charged first alpha helix (H1) of PrP. It has been proposed that two putative asparagine-to-arginine intrahelical salt bridges stabilize H1 in PrPC yet form intermolecular ionic bonds with adjacent PrP molecules during conversion of PrPC to PrPSc (M. P. Morrissey and E. I. Shakhnovich, Proc. Natl. Acad. Sci. USA 96:11293-11298, 1999). Subsequent work (J. O. Speare et al., J. Biol. Chem. 278:12522-12529, 2003 using a cell-free assay of PrPSc conversion suggested that rather than promoting conversion, the salt bridges stabilize PrPC against it. However, the role of individual H1 charges in PrPSc generation has not yet been investigated. To approach this question, we systematically reversed or neutralized each charged residue in H1 and tested the effect on conversion to PrPSc in scrapie-infected murine neuroblastoma (ScN2a) cells. We find that replacements of charged H1 residues with like charges permit conversion, while charge reversals hinder it. Neutralization of charges in the N-terminal (amino acids 143 to 146) but not the C-terminal (amino acids 147 to 151) half of H1 permits conversion, while complete reversal of charge orientation of the putative salt bridges produces a nonconvertible PrP. Circular dichroism spectroscopy studies and confocal microscopy immunofluorescence localization studies indicated that charge substitutions did not alter the secondary structure or cell surface expression of PrPC. These data support the necessity of specific charge orientations in H1 for a productive PrPSc-PrPC complex.

scholarly journals Role of the Varicella-Zoster Virus gB Cytoplasmic Domain in gB Transport and Viral Egress

2002 ◽  
Vol 76 (2) ◽  
pp. 591-599 ◽  
Author(s):  
Thomas C. Heineman ◽  
Susan L. Hall
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Amino Acid ◽  
Varicella Zoster Virus ◽  
Cultured Cells ◽  
Signal Sequence ◽  
Cytoplasmic Domain ◽  
Varicella Zoster ◽  
Golgi Transport ◽  
Viral Egress

ABSTRACT To study the function of the varicella-zoster virus (VZV) gB cytoplasmic domain during viral infection, we produced a VZV recombinant virus that expresses a truncated form of gB lacking the C-terminal 36 amino acids of its cytoplasmic domain (VZV gB-36). VZV gB-36 replicates in noncomplementing cells and grows at a rate similar to that of native VZV. However, cells infected with VZVgB-36 form extensive syncytia compared to the relatively small syncytia formed during native VZV infection. In addition, electron microscopy shows that very little virus is present on the surfaces of cells infected with VZV gB-36, while cells infected with native VZV exhibit abundant virions on the cell surface. The C-terminal 36 amino acids of the gB cytoplasmic domain have been shown in transfection-based experiments to contain both an endoplasmic reticulum-to-Golgi transport signal (the C-terminal 17 amino acids) and a consensus YXXφ (where Y is tyrosine, X is any amino acid, and φ is any bulky hydrophobic amino acid) signal sequence (YSRV) that mediates the internalization of gB from the plasma membrane. As predicted based on these data, gB-36 expressed during the infection of cultured cells is transported inefficiently to the Golgi. Despite lacking the YSRV signal sequence, gB-36 is internalized from the plasma membrane; however, in contrast to native gB, it fails to localize to the Golgi. Therefore, the C-terminal 36 amino acids of the VZV gB cytoplasmic domain are required for normal viral egress and for both the pre- and post-Golgi transport of gB.

The Effect of Insulin on the Growth and Metabolism of the Human Diploid Cell, Wi-38

1970 ◽  
Vol 7 (2) ◽  
pp. 575-585
Author(s):  
J. B. GRIFFITHS
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Glucose Uptake ◽  
Rna Synthesis ◽  
Cultured Cells ◽  
Cell Sheet ◽  
High Energy ◽  
Contact Inhibition ◽  
Contributory Factor ◽  
Membrane Area

In a confluent culture of WI-38 cells the membrane area available for nutrient uptake is greatly reduced and the possibility exists that this reduction in uptake capacity of the cell is a contributory factor in contact inhibition. Insulin has been reported by many authors to facilitate glucose uptake and also to stimulate protein, DNA and RNA synthesis, glycolysis, pino-cytosis and growth in cultured cells. The effect of insulin on WI-38 cells was determined, therefore, to find out whether it enabled the cell to escape from contact inhibition of growth. The action of insulin was found to be dependent upon medium composition. Growth and protein synthesis were stimulated in Eagle's minimal essential medium, but not when this medium was supplemented with glucose and glutamine. Apparently insulin is only effective when high-energy compounds become limiting. Whilst insulin did not induce any post-confluent division, the protein content of cells was increased by 30%, and this was correlated with an increased rate of protein synthesis. Despite this increased activity in protein metabolism, the utilization of amino acids was less in the presence of insulin indicating that a control mechanism for more economical utilization of amino acids for protein synthesis was activated by insulin. Insulin had no effect on RNA synthesis, and only a slight inhibitory effect on DNA synthesis. Evidence was produced suggesting that insulin blocked cell division and encouraged differentiation. Glucose uptake and incorporation into the cell was stimulated by insulin, and this was especially noticeable after the cell sheet became confluent. The turnover of labelled glucose and derivatives was also enhanced by insulin and this was accompanied by a much higher rate of lactic acid production. It is concluded that insulin does not overcome contact inhibition and permit post-confluent division, but that it does enable the cell to take up and utilize nutrients more efficiently in confluent cultures with a resultant increase in metabolic activity and cell size.

scholarly journals The uptake of tau amyloid fibrils is facilitated by the cellular prion protein and hampers prion propagation in cultured cells

2020 ◽  
Vol 155 (5) ◽  
pp. 577-591 ◽  
Author(s):  
Elena De Cecco ◽  
Luigi Celauro ◽  
Silvia Vanni ◽  
Micaela Grandolfo ◽  
Edoardo Bistaffa ◽  
...  
Keyword(s):  
Prion Protein ◽  
Amyloid Fibrils ◽  
Cultured Cells ◽  
Cellular Prion Protein ◽  
Prion Propagation

Amino acids as modulators of endothelium-derived nitric oxide

2006 ◽  
Vol 291 (2) ◽  
pp. F297-F304 ◽  
Author(s):  
Masao Kakoki ◽  
Hyung-Suk Kim ◽  
Cora-Jean S. Edgell ◽  
Nobuyo Maeda ◽  
Oliver Smithies ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Amino Acids ◽  
Endothelial Cells ◽  
Cultured Cells ◽  
Rat Kidney ◽  
No Production ◽  
Renal Vasculature ◽  
Cationic Amino Acid ◽  
Neutral Amino Acids ◽  
Cationic Amino Acids

To examine the mechanisms whereby amino acids modulate nitric oxide (NO) production and blood flow in the renal vasculature, chemiluminescence techniques were used to quantify NO in the renal venous effluent of the isolated, perfused rat kidney as different amino acids were added to the perfusate. The addition of 10−4 or 10−3 M cationic amino acids (l-ornithine, l-lysine, or l-homoarginine) or neutral amino acids (l-glutamine, l-leucine, or l-serine) to the perfusate decreased NO and increased renal vascular resistance. Perfusion with anionic amino acids (l-glutamate or l-aspartate) had no effect on either parameter. The effects of the cationic and neutral amino acids were reversed with 10−3 M l-arginine and prevented by deendothelialization or NO synthase inhibition. The effects of the neutral amino acids but not the cationic amino acids were dependent on extracellular sodium. Cationic and neutral amino acids also decreased calcimycin-induced NO, as assessed by DAF-FM-T fluorescence, in cultured EA.hy926 endothelial cells. Inhibition of system y+ or y+L by siRNA for the cationic amino acid transporter 1 or the CD98/4F2 heavy chain diminished the NO-depleting effects of these amino acids. Finally, transport studies in cultured cells demonstrated that cationic or neutral amino acids in the extracellular space stimulate efflux of l-arginine out of the cell. Thus the present experiments demonstrate that cationic and neutral amino acids can modulate NO production in endothelial cells by altering cellular l-arginine transport through y+ and y+L transport mechanisms.

Review: Role of tubal environment in preimplantation embryogenesis: application to co-culture assays

Zygote ◽  
2010 ◽  
Vol 19 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Pierre Guérin ◽  
Yves Ménézo
Keyword(s):  
Amino Acids ◽  
Embryo Culture ◽  
Metabolic Flux ◽  
Cultured Cells ◽  
Culture Media ◽  
Culture Conditions ◽  
Antioxidant Compounds ◽  
Beneficial Effects ◽  
Stage Embryo

SummaryThe culture of early preimplantation stage embryo is still delicate and the metabolic pathways of embryos are not completely understood. Embryo needs are evolutionary during the preimplantation development, consequently it is difficult to meet embryo needs in vitro. Culture conditions have to respect several physical and chemical equilibria: such as redox potential, pH, osmotic pressure, metabolic flux of energetic compounds, endogenous pools of amino acids and transcripts, etc. Embryo culture media are generally supplemented with amino acids, glucose, other energetic metabolites and antioxidant compounds, vitamin, and growth factors etc. Furthermore autocrine and paracrine regulation of embryo development probably exist. In fact embryo culture conditions have to be as non-toxic as possible. Various types of co-culture systems have been devised to overcome these problems. Complex interrelations exist between embryos and co-cultured cells. The beneficial effects of co-cultured cells may be due to continuous modifications of the culture medium, i.e. the elimination of toxic compounds and/or the supply of embryotrophic factors.

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