scholarly journals A Mutually Inhibitory Feedback Loop between the 20S Proteasome and Its Regulator, NQO1

2012 ◽  
Vol 47 (1) ◽  
pp. 76-86 ◽  
Author(s):  
Oren Moscovitz ◽  
Peter Tsvetkov ◽  
Nimrod Hazan ◽  
Izhak Michaelevski ◽  
Hodaya Keisar ◽  
...  
Keyword(s):  
Feedback Loop ◽  
20S Proteasome ◽  
Inhibitory Feedback

Inhibitory Feedback Loop Induces Anticipated Synchronization in Neuronal Networks

2014 ◽  
Vol 1 ◽  
pp. 636-639
Author(s):  
Fernanda S. Matias ◽  
Pedro V. Carelli ◽  
Claudio R. Mirasso ◽  
Mauro Copelli
Keyword(s):  
Feedback Loop ◽  
Neuronal Networks ◽  
Inhibitory Feedback

scholarly journals Inhibitory Feedback Loop Between Tolerogenic Dendritic Cells and Regulatory T Cells in Transplant Tolerance

2003 ◽  
Vol 170 (3) ◽  
pp. 1304-1312 ◽  
Author(s):  
Wei-Ping Min ◽  
Dejun Zhou ◽  
Thomas E. Ichim ◽  
Gill H. Strejan ◽  
Xiaoping Xia ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Regulatory T Cells ◽  
Feedback Loop ◽  
Transplant Tolerance ◽  
Tolerogenic Dendritic Cells ◽  
Inhibitory Feedback

scholarly journals Evidence for an inhibitory feedback loop regulating simian virus 40 large T-antigen fusion protein nuclear transport

1996 ◽  
Vol 315 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Ulrich SEYDEL ◽  
David A. JANS
Keyword(s):  
Nuclear Import ◽  
Feedback Loop ◽  
Protein Import ◽  
Nuclear Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Nuclear Accumulation ◽  
Large T Antigen ◽  
Inhibitory Feedback

Nuclear protein import is central to eukaryotic cell function. It is dependent on ATP, temperature and cytosolic factors, and requires specific targeting sequences called nuclear localization signals (NLSs). Nuclear import kinetics was studied in vitro using digitonin-permeabilized cells of the HTC rat hepatoma cell line and a fluorescently labelled β-galactosidase fusion protein carrying amino acids 111–135 of the simian virus 40 large T-antigen (T-ag), including the NLS. Nuclear accumulation was rapid, reaching steady-state after about 80 min at 37 °C (t1/2 at about 17 min). Surprisingly, maximal nuclear concentration was found to be directly proportional to the concentration of the cytosolic extract and of cytoplasmic T-ag protein. Neither preincubation of cells for 1 h at 37 °C before the addition of T-ag protein nor the addition of fresh transport medium after 1 h and continuation of the incubation for another hour affected the maximal nuclear concentration. If cells were allowed to accumulate T-ag protein for 1 h before the addition of fresh transport medium containing different concentrations of T-ag protein and incubated for a further hour, the maximal nuclear concentration did not change unless the concentration of T-ag protein in the second transport mixture exceeded that in the first, in which case the nuclear concentration increased. Nuclear import of T-ag thus appeared (i) to be strictly unidirectional over 2 h at 37 °C and (ii) to be regulated by an inhibitory feedback loop, whereby the cytosolic concentration of protein appears to determine directly the precise end point of nuclear accumulation. This study represents the first characterization of this previously undescribed mechanism of regulation of nuclear protein import.

Conditions required for the inhibitory feedback loop in noradrenergic transmission

Nature ◽  
1981 ◽  
Vol 293 (5827) ◽  
pp. 62-65 ◽  
Author(s):  
D. F. Story ◽  
M. W. McCulloch ◽  
M. J. Rand ◽  
C. A. Standford-Starr
Keyword(s):  
Feedback Loop ◽  
Noradrenergic Transmission ◽  
Inhibitory Feedback

The Drosophila embryonic midline is the site of Spitz processing, and induces activation of the EGF receptor in the ventral ectoderm

Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3363-3370 ◽  
Author(s):  
M. Golembo ◽  
E. Raz ◽  
B.Z. Shilo
Keyword(s):  
Feedback Loop ◽  
Egf Receptor ◽  
Ectopic Expression ◽  
Cell Fates ◽  
Inhibitory Feedback ◽  
Midline Cells ◽  
Stable Source

The Drosophila EGF receptor (DER) is activated by secreted Spitz to induce different cell fates in the ventral ectoderm. Processing of the precursor transmembrane Spitz to generate the secreted form was shown to be the limiting event, but the cells in which processing takes place and the mechanism that may generate a gradient of secreted Spitz in the ectoderm were not known. The ectodermal defects in single minded (sim) mutant embryos, in which the midline fails to develop, suggested that the midline cells contribute to patterning of the ventral ectoderm. This work shows that the midline provides the site for Spitz expression and processing. The Rhomboid and Star proteins are also expressed and required in the midline. The ectodermal defects of spitz, rho or Star mutant embryos could be rescued by inducing the expression of the respective normal genes only in the midline cells. Rho and Star thus function non-autonomously, and may be required for the production or processing of the Spitz precursor. Secreted Spitz is the only sim-dependent contribution of the midline to patterning the ectoderm, since the ventral defects observed in sim mutant embryos can be overcome by expression of secreted Spitz in the ectoderm. While ectopic expression of secreted Spitz in the ectoderm or mesoderm gave rise to ventralization of the embryo, increased expression of secreted Spitz in the midline did not lead to alterations in ectoderm patterning. A mechanism for adjustment to variable levels of secreted Spitz emanating from the midline may be provided by Argos, which forms an inhibitory feedback loop for DER activation. The production of secreted Spitz in the midline, may provide a stable source for graded DER activation in the ventral ectoderm.

What is a biological oscillator?

1984 ◽  
Vol 246 (6) ◽  
pp. R847-R853 ◽  
Author(s):  
W. O. Friesen ◽  
G. D. Block
Keyword(s):  
Smooth Muscle ◽  
Qualitative Analysis ◽  
Feedback Loop ◽  
Feedback Inhibition ◽  
Essential Elements ◽  
Molluscan Neuron ◽  
Biological Oscillators ◽  
Biological Oscillator ◽  
Inhibitory Feedback ◽  
Smooth Muscle Contractions

Biological oscillators are amenable to qualitative analysis even before they have been described exhaustively in quantitative terms. Qualitative analysis can identify the elements essential for generating the oscillations and can enhance our understanding of underlying oscillator mechanisms. Two essential elements of a biological oscillator are 1) an inhibitory feedback loop, which includes one or more oscillating variables, and 2) a source of delay in this feedback loop, which allows an oscillating variable to overshoot a steady-state value before the feedback inhibition is fully effective. The analysis of the patterns of interactions and delays observed in biological oscillators is simplified by the translation of variables, interactions, and delays into schematic representations. To illustrate how such translations can be implemented, three biological oscillators are described schematically: 1) the glycolytic oscillator, 2) the bursting of the molluscan neuron, R15, and 3) the oscillations underlying smooth muscle contractions.

scholarly journals An Fgf/Gremlin inhibitory feedback loop triggers termination of limb bud outgrowth

Nature ◽  
2008 ◽  
Vol 454 (7204) ◽  
pp. 638-641 ◽  
Author(s):  
Jamie M. Verheyden ◽  
Xin Sun
Keyword(s):  
Feedback Loop ◽  
Limb Bud ◽  
Inhibitory Feedback
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