scholarly journals Calcium-engaged Mechanisms of Nongenomic Action of Neurosteroids

2017 ◽  
Vol 15 (8) ◽  
Author(s):  
Elzbieta Rebas ◽  
Tomasz Radzik ◽  
Tomasz Boczek ◽  
Ludmila Zylinska
Keyword(s):  
2005 ◽  
Vol 73 (2) ◽  
pp. 214-221 ◽  
Author(s):  
Mercedes Perusquía ◽  
Erika Navarrete ◽  
Jaime Jasso-Kamel ◽  
Luis M. Montaño

2005 ◽  
Vol 25 (18) ◽  
pp. 8273-8284 ◽  
Author(s):  
Fuzhong F. Zheng ◽  
Ray-Chang Wu ◽  
Carolyn L. Smith ◽  
Bert W. O'Malley

ABSTRACT SRC-3/AIB1/ACTR/pCIP/RAC3/TRAM1 is a primary transcriptional coregulator for estrogen receptor (ER). Six SRC-3 phosphorylation sites have been identified, and these can be induced by steroids, cytokines, and growth factors, involving multiple kinase signaling pathways. Using phosphospecific antibodies for six phosphorylation sites, we investigated the mechanisms involved in estradiol (E2)-induced SRC-3 phosphorylation and found that this occurs only when either activated estrogen receptor α (ERα) or activated ERβ is present. Both the activation function 1 and the ligand binding domains of ERα are required for maximal induction. Mutations in the coactivator binding groove of the ERα ligand binding domain inhibit E2-stimulated SRC-3 phosphorylation, as do mutations in the nuclear receptor-interacting domain of SRC-3, suggesting that ERα must directly contact SRC-3 for this posttranslational modification to take place. A transcriptionally inactive ERα mutant which localizes to the cytoplasm supports E2-induced SRC-3 phosphorylation. Mutations of the ERα DNA binding domain did not block this rapid E2-dependent SRC-3 phosphorylation. Together these data demonstrate that E2-induced SRC-3 phosphorylation is dependent on a direct interaction between SRC-3 and ERα and can occur outside of the nucleus. Our results provide evidence for an early nongenomic action of ER on SRC-3 that supports the well-established downstream genomic roles of estrogen and coactivators.


2011 ◽  
Vol 300 (3) ◽  
pp. F682-F691 ◽  
Author(s):  
D. C. A. Leite-Dellova ◽  
G. Malnic ◽  
M. Mello-Aires

The genomic and nongenomic effects of aldosterone on the intracellular pH recovery rate (pHirr) via H+-ATPase and on cytosolic free calcium concentration ([Ca2+]i) were investigated in isolated proximal S3 segments of rats during superfusion with an Na+-free solution, by using the fluorescent probes BCECF-AM and FLUO-4-AM, respectively. The pHirr, after cellular acidification with a NH4Cl pulse, was 0.064 ± 0.003 pH units/min ( n = 17/74) and was abolished with concanamycin. Aldosterone (10−12, 10−10, 10−8, or 10−6 M with 1-h or 15- or 2-min preincubation) increased the pHirr. The baseline [Ca2+]i was 103 ± 2 nM ( n = 58). After 1 min of aldosterone preincubation, there was a transient and dose-dependent increase in [Ca2+]i and after 6-min preincubation there was a new increase in [Ca2+]i that persisted after 1 h. Spironolactone [mineralocorticoid (MR) antagonist], actinomycin D, or cycloheximide did not affect the effects of aldosterone (15- or 2-min preincubation) on pHirr and on [Ca2+]i but inhibited the effects of aldosterone (1-h preincubation) on these parameters. RU 486 [glucocorticoid (GR) antagonist] and dimethyl-BAPTA (Ca2+ chelator) prevented the effect of aldosterone on both parameters. The data indicate a genomic (1 h, via MR) and a nongenomic action (15 or 2 min, probably via GR) on the H+-ATPase and on [Ca2+]i. The results are compatible with stimulation of the H+-ATPase by increases in [Ca2+]i (at 10−12-10−6 M aldosterone) and inhibition of the H+-ATPase by decreases in [Ca2+]i (at 10−12 or 10−6 M aldosterone plus RU 486).


1998 ◽  
Vol 83 (7) ◽  
pp. 2313-2316 ◽  
Author(s):  
Paul A. Komesaroff ◽  
Catherine V.S. Black ◽  
Roderick A. Westerman

1999 ◽  
Vol 84 (5) ◽  
pp. 1670-1678 ◽  
Author(s):  
Michaela Luconi ◽  
Monica Muratori ◽  
Gianni Forti ◽  
Elisabetta Baldi

The presence of a novel functional estrogen receptor on the human sperm surface has been demonstrated by using different experimental approaches. Ligand blot analysis of sperm lysates, using peroxidase-conjugated estradiol as probe, identified a specific estradiol-binding protein of approximately 29-kDa apparent molecular mass. The same protein band was also revealed by using αH222 antibody, which is directed against the steroid binding domain of the genomic estrogen receptor. The biological effects of estrogen receptor were investigated by analyzing calcium fluxes, tyrosine phosphorylation, and acrosome reaction (AR) in response to 17β-estradiol (17βE2) and by measuring the steroid influence on calcium and AR in responses to progesterone (P), a well-known physiological stimulus for human spermatozoa. Our results demonstrate that 17βE2 induces a rapid and sustained increase of intracellular calcium concentrations ([Ca2+]i). This effect is totally dependent on the presence of extracellular calcium, because it is completely abolished in a calcium-depleted medium. The dose-response curve for calcium increase to 17βE2 is biphasic with a first component in the nanomolar range (effective concentration 50 = 0.60 ± 0.12 nmol/L) and a second component in the micromolar range (EC50 = 3.80 ± 0.26 μmol/L). 17βE2 stimulates tyrosine phosphorylation of several sperm proteins, including the 29-kDa protein band, and determines a reduction of calcium response to P, finally resulting in inhibition of P-stimulated sperm AR. Conversely, no direct effect of 17βE2 is observed on AR. 17βE2 effects on calcium are clearly mediated by a membrane receptor, because they are reproduced by the membrane-impermeable conjugate of the hormone BSA-E2 and reduced by sperm preincubation with αH222 antibody. Taken together, our results clearly show the presence of a functional surface estrogen receptor, of 29 kDa, on human spermatozoa. This receptor may play a role in the modulation of nongenomic action of P in these cells during the process of fertilization.


Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 773-780 ◽  
Author(s):  
Anastasia S. Mihailidou ◽  
Mahidi Mardini ◽  
John W. Funder

Abstract Aldosterone elevates Na+/K+/2Cl− cotransporter activity in rabbit cardiomyocytes within 15 min, an effect blocked by K-canrenoate and thus putatively mineralocorticoid receptor mediated. Increased cotransporter activity raises intracellular [Na+] sufficient to produce a secondary increase in Na+-K+ pump activity; when this increase in intracellular [Na+] is prevented, a rapid effect of aldosterone to lower pump activity is seen. Addition of transcription inhibitor actinomycin D did not change basal or aldosterone-induced lowered pump activity, indicating a direct, nongenomic action of aldosterone. We examined a possible role for protein kinase C (PKC) in the rapid nongenomic effects of aldosterone. Single ventricular myocytes and pipette solutions containing 10 mm intracellular [Na+] were used in patch clamp studies to measure Na+-K+ pump activity. Aldosterone lowered pump current, an effect abolished by ε PKC (εPKC) inhibition but neither αPKC nor scrambled εPKC; addition of εPKC activator peptide mimicked the rapid aldosterone effect. In rabbits chronically infused with aldosterone, the lowered pump current in cardiomyocytes was acutely (≤15 min) restored by εPKC inhibition. These studies show that rapid effects of aldosterone on Na+-K+ pump activity are nongenomic and specifically εPKC mediated; in addition, such effects may be prolonged (7 d) and long-lived (∼4 h isolated cardiomyocyte preparation time). The rapid, prolonged, long-lived effects can be rapidly (≤15 min) reversed by εPKC blockade, suggesting a hitherto unrecognized complexity of aldosterone action in the heart and perhaps by extension other tissues.


2013 ◽  
Vol 305 (5) ◽  
pp. C547-C557 ◽  
Author(s):  
Wen-Hao Dong ◽  
Jia-Chen Chen ◽  
Yan-Lin He ◽  
Jia-Jie Xu ◽  
Yan-Ai Mei

Resveratrol (REV) is a naturally occurring phytoalexin that inhibits neuronal K+ channels; however, the molecular mechanisms behind the effects of REV and the relevant α-subunit are not well defined. With the use of patch-clamp technique, cultured cerebellar granule cells, and HEK-293 cells transfected with the Kv2.1 and Kv2.2 α-subunits, we investigated the effect of REV on Kv2.1 and Kv2.2 α-subunits. Our data demonstrated that REV significantly suppressed Kv2.2 but not Kv2.1 currents with a fast, reversible, and mildly concentration-dependent manner and shifted the activation or inactivation curve of Kv2.2 channels. Activating or inhibiting the cAMP/PKA pathway did not abolish the inhibition of Kv2.2 current by REV. In contrast, activation of PKC with phorbol 12-myristate 13-acetate mimicked the inhibitory effect of REV on Kv2.2 by modifying the activation or inactivation properties of Kv2.2 channels and eliminated any further inhibition by REV. PKC and PKC-α inhibitor completely eliminated the REV-induced inhibition of Kv2.2. Moreover, the effect of REV on Kv2.2 was reduced by preincubation with antagonists of GPR30 receptor and shRNA for GPR30 receptor. Western blotting results indicated that the levels of PKC-α and PKC-β were significantly increased in response to REV application. Our data reveal, for the first time, that REV inhibited Kv2.2 currents through PKC-dependent pathways and a nongenomic action of the oestrogen receptor GPR30.


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