Subnuclear Trafficking of Glucocorticoid Receptors

Author(s):  
Uma R. Chandran ◽  
Donald B. DeFranco
1997 ◽  
Vol 137 (3) ◽  
pp. 523-538 ◽  
Author(s):  
Jun Yang ◽  
Jimin Liu ◽  
Donald B. DeFranco

We have used digitonin-permeabilized cells to examine in vitro nuclear export of glucocorticoid receptors (GRs). In situ biochemical extractions in this system revealed a distinct subnuclear compartment, which collects GRs that have been released from chromatin and serves as a nuclear export staging area. Unliganded nuclear GRs within this compartment are not restricted in their subnuclear trafficking as they have the capacity to recycle to chromatin upon rebinding hormone. Thus, GRs that release from chromatin do not require transit through the cytoplasm to regain functionality. In addition, chromatin-released receptors export from nuclei of permeabilized cells in an ATP- and cytosol-independent process that is stimulated by sodium molybdate, other group VI-A transition metal oxyanions, and some tyrosine phosphatase inhibitors. The stimulation of in vitro nuclear export by these compounds is not unique to GR, but is restricted to other proteins such as the 70- and 90-kD heat shock proteins, hsp70 and hsp90, respectively, and heterogeneous nuclear RNP (hnRNP) A1. Under analogous conditions, the 56-kD heat shock protein, hsp56, and hnRNP C do not export from nuclei of permeabilized cells. If tyrosine kinase inhibitors genistein and tyrphostin AG126 are included to prevent increased tyrosine phosphorylation, in vitro nuclear export of GR is inhibited. Thus, our results are consistent with the involvement of a phosphotyrosine system in the general regulation of nuclear protein export, even for proteins such as GR and hnRNP A1 that use distinct nuclear export pathways.


2004 ◽  
Vol 36 (05) ◽  
Author(s):  
K Krieger ◽  
A Klimke ◽  
U Henning

2020 ◽  
Vol 24 (4) ◽  
pp. 9-20
Author(s):  
Ya. F. Zverev ◽  
A. Ya. Rykunova

The review is devoted to the consideration of the most common drugs currently used in the treatment of primary nephrotic syndrome. Mechanisms of pharmacological activity of glucocorticosteroids, ACTH, calcineurin inhibitors cyclosporine A and tacrolimus, alkylating compounds cyclophosphamide and chlorambucil, mycophenolate mofetil, levamisole, abatacept, rituximab and a number of other recently created monoclonal antibodies. An attempt is made to separate the immune and non-immune mechanisms of action of the most common drugs, concerning both the impact on the immunogenetics of the noted diseases and the direct impact on the podocytes that provide permeability of the glomerular filtration barrier and the development of proteinuria. It is shown that the immune mechanisms of corticosteroids are caused by interaction with glucocorticoid receptors of lymphocytes, and nonimmune – with stimulation of the same receptors in podocytes. It was found that the activation of adrenocorticotropic hormone melanocortin receptors contributes to the beneficial effect of the drug in nephrotic syndrome. It is discussed that the immune mechanism of calcineurin inhibitors is provided by the suppression of tissue and humoral immunity, and the non-immune mechanism is largely due to the preservation of the activity of podocyte proteins such as synaptopodin and cofilin. Evidence is presented to show that the beneficial effect of rituximab in glomerulopathies is related to the interaction of the drug with the protein SMPDL-3b in lymphocytes and podocytes. The mechanisms of action of mycophenolate mofetil, inhibiting the activity of the enzyme inosine 5-monophosphate dehydrogenase, which causes the suppression of the synthesis of guanosine nucleotides in both lymphocytes and glomerular mesangium cells, are considered. It is emphasized that the effect of levamisole in nephrotic syndrome is probably associated with the normalization of the ratio of cytokines produced by various T-helpers, as well as with an increase in the expression and activity of glucocorticoid receptors. The mechanisms of pharmacological activity of a number of monoclonal antibodies, as well as galactose, the beneficial effect of which may be provided by binding to the supposed permeability factor produced by lymphocytes, are considered.


Author(s):  
Saniya Hashim Khan ◽  
Sheraz Khan ◽  
Inamullah Khan ◽  
Narmeen Hashim

Background: Chronic stress elevates the cortisol beyond normal levels, which affects cognition including learning & memory. This injurious effect is primarily mediated via over excitation of metabotropic glucocorticoid receptors (mGR). Methods: The present study was aimed appraise the neuroprotective effects of naturally occurring molecule β-1,3-glucan by interfering with stress-cortisol-mGR axis. Our data of virtual screening (in silico) exhibited the promising interactions of βglucan with the mGR. Therefore, the study was extended to evaluate its efficacy (2.5, 5 and 10 mg/kg/ i.p) in an animal model of chronic unpredictable mild stress (CUMS, 28 days) induced memory impairment. Results: Results of the current study revealed the β-glucan provided dose dependent protection against deleterious effects of stress on learning and memory associated parameters observed in Morris water maze (MWM) task. At higher tested doses, it has also significantly antagonized the stress induced weight loss and corticosterone elevation. Conclusion: From these findings, it can be deduced that the β-glucan possesses therapeutic potential against stress induced memory impairment, and this effect can be attributed to its normalizing effect on corticosterone levels.


Author(s):  
Leandro F. Vendruscolo ◽  
George F. Koob

Alcohol use disorder is a chronically relapsing disorder that involves (1) compulsivity to seek and take alcohol, (2) difficulty in limiting alcohol intake, and (3) emergence of a negative emotional state (e.g., dysphoria, anxiety, irritability) in the absence of alcohol. Alcohol addiction encompasses a three-stage cycle that becomes more intense as alcohol use progresses: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. These stages engage neuroadaptations in brain circuits that involve the basal ganglia (reward hypofunction), extended amygdala (stress sensitization), and prefrontal cortex (executive function disorder). This chapter discusses key neuroadaptations in the hypothalamic and extrahypothalamic stress systems and the critical role of glucocorticoid receptors. These neuroadaptations contribute to negative emotional states that powerfully drive compulsive alcohol drinking and seeking. These changes in association with a disruption of prefrontal cortex function that lead to cognitive deficits and poor decision making contribute to the chronic relapsing nature of alcohol dependence.


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