In vitro and in vivo thermal activation of steroid-receptor complexes from rats and ground squirrels (Spermophilus citellus)

1995 ◽  
Vol 110 (2) ◽  
pp. 451-462 ◽  
Author(s):  
Dragoslava Živadinović ◽  
R.K. Andjus
Keyword(s):  
Thermal Activation ◽  
Steroid Receptor ◽  
Ground Squirrels ◽  
Receptor Complexes ◽  
Spermophilus Citellus

scholarly journals Nuclear acceptor sites for androgen-receptor complexes in seminal-vesicle epithelium

1980 ◽  
Vol 192 (1) ◽  
pp. 41-47 ◽  
Author(s):  
M J Weinberger ◽  
C M Veneziale
Keyword(s):  
Seminal Vesicle ◽  
Nuclear Dna ◽  
Steroid Receptor ◽  
Assay Method ◽  
Scatchard Analysis ◽  
Receptor Complex ◽  
Receptor Complexes ◽  
Constant Slope

An assay method in vitro was developed and applied to quantify acceptor binding of steroid-receptor complexes in nuclei from isolated epithelium of guinea-pig seminal vesicle. Steroid-receptor complex prepared from 1-day-castrated animals was incubated with purified nuclei from 1-28 day-castrated animals in a medium containing 0.15 M-KCl. Free and bound steroid-receptor complexes were measured and the data were submitted to Scatchard analysis. With nuclei from 1-day-castrated animals the Kd for binding of cytosolic [3H]dihydrotestosterone-receptor complexes was found to be 0.83 × 10(-10) M and the capacity for binding was 0.35 pmol/mg of nuclear DNA. Scatchard analysis consistently disclosed only a single line of constant slope and gave the same kinetic constants for nuclei obtained from animals castrated up to 28 days before assay. Administration of 2 mg of dihydrotestosterone, 3 alpha-androstanediol or androsterone or 100 microgram of oestradiol-17 beta 1 h before killing of the 1-day-castrated animals that provided the nuclei resulted in a significant decrease in nuclear acceptor binding of the steroid-receptor complex compared with untreated animals. Thus our assay method disclosed nuclear acceptor sites that may be involved in responses to androgens (and oestrogens) in vivo. We conclude that there is a class of nuclear accept or sites of high affinity and limited capacity that may be occupied by steroid-receptor complexes in vivo.

scholarly journals Essential Role for Co-chaperone Fkbp52 but Not Fkbp51 in Androgen Receptor-mediated Signaling and Physiology

2006 ◽  
Vol 282 (7) ◽  
pp. 5026-5036 ◽  
Author(s):  
Weidong Yong ◽  
Zuocheng Yang ◽  
Sumudra Periyasamy ◽  
Hanying Chen ◽  
Selcul Yucel ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Nuclear Translocation ◽  
Steroid Receptor ◽  
Hormone Binding ◽  
Receptor Complexes ◽  
Deficient Mice

Fkbp52 and Fkbp51 are tetratricopeptide repeat proteins found in steroid receptor complexes, and Fkbp51 is an androgen receptor (AR) target gene. Although in vitro studies suggest that Fkbp52 and Fkbp51 regulate hormone binding and/or subcellular trafficking of receptors, the roles of Fkbp52 and Fkbp51 in vivo have not been extensively investigated. Here, we evaluate their physiological roles in Fkbp52-deficient and Fkbp51-deficient mice. Fkbp52-deficient males developed defects in select reproductive organs (e.g. penile hypospadias and prostate dysgenesis but normal testis), pointing to a role for Fkbp52 in AR-mediated signaling and function. Surprisingly, ablation of Fkbp52 did not affect AR hormone binding or nuclear translocation in vivo and in vitro. Molecular studies in mouse embryonic fibroblast cells uncovered that Fkbp52 is critical to AR transcriptional activity. Interestingly, Fkbp51 expression was down-regulated in Fkbp52-deficient males but only in affected tissues, providing further evidence of tissue-specific loss of AR activity and suggesting that Fkbp51 is an AR target gene essential to penile and prostate development. However, Fkbp51-deficient mice were normal, showing no defects in AR-mediated reproductive function. Our work demonstrates that Fkbp52 but not Fkbp51 is essential to AR-mediated signaling and provides evidence for an unprecedented Fkbp52 function, direct control of steroid receptor transcriptional activity.

scholarly journals Resistance of Erythrocytes of Hibernating Mammals to Loss of Potassium during Hibernation and during Cold Storage

1971 ◽  
Vol 58 (6) ◽  
pp. 620-633 ◽  
Author(s):  
S. L. Kimzey ◽  
J. S. Willis
Keyword(s):  
Ground Squirrel ◽  
Normal Values ◽  
Ground Squirrels ◽  
Storage Medium ◽  
Cold Adapted ◽  
Maximum Period ◽  
K Concentration

In two species of hibernators, hamsters and ground squirrels, erythrocytes were collected by heart puncture and the K content of the cells of hibernating individuals was compared with that of awake individuals. The K concentration of hamsters did not decline significantly during each bout of hibernation (maximum period of 5 days) but in long-term bouts in ground squirrels (i.e. more than 5 days) the K concentration of cells dropped significantly. When ground squirrels were allowed to rewarm the K content of cells rose toward normal values within a few hours. Erythrocytes of both hamsters and ground squirrels lose K more slowly than those of guinea pigs (nonhibernators) when stored in vitro for up to 10 days at 5°C. In ground squirrels the rate of loss of K during storage is the same as in vivo during hibernation, and stored cells taken from hibernating ground squirrels also lose K at the same rate. The rate of loss of K from guinea pig cells corresponded with that predicted from passive diffusion unopposed by transport. The actual rate of loss of K from ground squirrel cells was slower than such a predicted rate but corresponded with it when glucose was omitted from the storage medium or ouabain was added to it. Despite the slight loss of K that may occur in hibernation, therefore, the cells of hibernators are more cold adapted than those of a nonhibernating mammal, and this adaptation depends in part upon active transport.

scholarly journals ESR1 Mutations Associated With Estrogen Insensitivity Syndrome Change Conformation of Ligand-Receptor Complex and Altered Transcriptome Profile

Endocrinology ◽  
2020 ◽  
Vol 161 (6) ◽  
Author(s):  
Yin Li ◽  
Katherine J Hamilton ◽  
Lalith Perera ◽  
Tianyuan Wang ◽  
Artiom Gruzdev ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Reproductive Tract ◽  
Biological Effects ◽  
Estrogen Receptor Α ◽  
Female Reproductive Tract ◽  
Receptor Complexes ◽  
Esr1 Gene ◽  
Esr1 Mutations

Abstract Estrogen insensitivity syndrome (EIS) arises from rare mutations in estrogen receptor-α (ERα, encoded by ESR1 gene) resulting in the inability of estrogen to exert its biological effects. Due to its rarity, mutations in ESR1 gene and the underlying molecular mechanisms of EIS have not been thoroughly studied. Here, we investigate known ESR1 mutants, Q375H and R394H, associated with EIS patients using in vitro and in vivo systems. Comparison of the transcriptome and deoxyribonucleic acid methylome from stable cell lines of both Q375H and R394H clinical mutants shows a differential profile compared with wild-type ERα, resulting in loss of estrogen responsiveness. Molecular dynamic simulation shows that both ESR1 mutations change the ERα conformation of the ligand-receptor complexes. Furthermore, we generated a mouse model Esr1-Q harboring the human mutation using CRISPR/Cas9 genome editing. Female and male Esr1-Q mice are infertile and have similar phenotypes to αERKO mice. Overall phenotypes of the Esr1-Q mice correspond to those observed in the patient with Q375H. Finally, we explore the effects of a synthetic progestogen and a gonadotropin-releasing hormone inhibitor in the Esr1-Q mice for potentially reversing the impaired female reproductive tract function. These findings provide an important basis for understanding the molecular mechanistic consequences associated with EIS.

Effect of theophylline on nuclear retention of oestrogen-receptor complexes: correlation with oestrogen responses

1985 ◽  
Vol 105 (3) ◽  
pp. 397-403
Author(s):  
J. Steinsapir ◽  
A. M. Rojas ◽  
M. E. Bruzzone ◽  
A. White ◽  
O. Alarcón ◽  
...  
Keyword(s):  
Body Weight ◽  
Oestrogen Receptor ◽  
Nuclear Retention ◽  
Adult Rat ◽  
Receptor Complexes ◽  
Wet Weight

ABSTRACT In the ovariectomized adult rat uterine oedema induced by 0·01 and 0·1 μg oestradiol-17β/100 g body weight increased further in the presence of theophylline. Nuclear retention of oestrogen-receptor complexes also increased in response to theophylline both in vivo and in vitro. Theophylline decreased the number of eosinophils in the blood and concurrently decreased oestrogen-induced uterine eosinophilia at doses of 0·001, 0·01, 0·1, 1, 10 or 30 μg oestradiol/100 g body weight, through a mechanism independent of glucocorticoids. There was, therefore, no correlation between changes in the number of uterine eosinophils and changes in uterine wet weight induced by theophylline and oestrogen. It is suggested that the presence of oestrogen-receptor complexes in the nucleus for at least 4 h is a prerequisite for the induction of uterine oedema and growth in the presence of theophylline and oestradiol-17β. J. Endocr. (1985) 105, 397–403

scholarly journals Interaction of nistranol with estradiol and progesterone receptors in the rat uterus cytosol in vitro and in vivo

1996 ◽  
Vol 42 (4) ◽  
pp. 33-34
Author(s):  
Ye. N. Kareva ◽  
V. P. Fedotov ◽  
V. M. Rzheznikov ◽  
Ye. V. Solovyova ◽  
Ye. V. Pokrovskaya
Keyword(s):  
Single Injection ◽  
Progesterone Receptors ◽  
Uterine Tissue ◽  
Rat Uterus ◽  
Cytosol Fraction ◽  
Receptor Complexes ◽  
Target Organs ◽  
Uterine Growth

Interactions between nistranol and estradiol and progesterone receptors in the cytosol fraction of the uterine tissue of oophorectomized rats and the relative competitive capacity of nistranol have been studied 24 h after a single injection of the drug. The results demonstrate the effects of nistranol on estradiol and progesterone binding. Nistranol boosting of uterine growth in rats is explained by its capacity to accelerate the translocation of hor- mone-receptor complexes into the nucleus. Investigations of the capacity of new estrogens to compete with estradiol for binding in the tissues of target organs in vitro and affect estradiol and progesterone binding in vivo permit a more effective screening of estrogens than use of only the classical in vitro method.

scholarly journals Potential ligand-receptor-pathway cascades and a novel non-metabolic function of lactate in remodeling uterine receptivity by inducing endometrial histone lactylation at implantation, revealed by a proteomic atlas of maternal-fetal crosstalk

2021 ◽  
Author(s):  
Qianying Yang ◽  
Juan Liu ◽  
Yue Wang ◽  
Wei Zhao ◽  
Wenjing Wang ◽  
...  
Keyword(s):  
Embryo Implantation ◽  
Redox Homeostasis ◽  
Integrated Analysis ◽  
Physical Interaction ◽  
Metabolic Function ◽  
Uterine Receptivity ◽  
Cellular Mechanisms ◽  
Receptor Complexes

Abstract Well-orchestrated maternal-fetal crosstalk involves secreted ligands, interacting receptors, and coupled pathways between the conceptus and endometrium. However, previous researches mainly focused on either the conceptus or endometrium in isolation. The lack of integrated analysis, especially on protein levels, has made it challenging to advance our understanding of the crosstalk. Herein, focusing on ligand–receptor complexes and coupled pathways at maternal-fetal interface in sheep, a well-established embryo implantation model, we provide the first comprehensive proteomic atlas of ligand-receptor-pathway cascades that may be essential for implantation. Based on these candidate interactions, we further revealed the physical interaction of albumin-claudin 4 and their role in facilitating embryo attachment to endometrium. More interestingly, we demonstrated a novel non-metabolic function of enhanced conceptus glycolysis in remodeling uterine receptivity, by inducing endometrial histone lactylation, a newly identified histone modification. Our results from in vitro and in vivo models supported the essential role of lactate, as a key embryonic signal, in regulating redox homeostasis and apoptotic balance to ensure successful implantation. Our study identified many putative molecular and cellular mechanisms that fine-tuned conceptus-endometrium crosstalk during implantation, thus providing important clues for developing potential clinical intervention strategies to improve pregnancy outcomes following both natural conception and assisted reproduction.

Effect of MM-141 on gemcitabine and nab-paclitaxel potentiation in preclinical models of pancreatic cancer through induction of IGF-1R and ErbB3 degradation.

2015 ◽  
Vol 33 (3_suppl) ◽  
pp. 289-289 ◽  
Author(s):  
Emily Pace ◽  
Sharlene Adams ◽  
Adam Camblin ◽  
Michael Curley ◽  
Victoria Rimkunas ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Pancreatic Adenocarcinoma ◽  
Cell Lines ◽  
Stage Iv ◽  
Akt Signaling ◽  
Preclinical Models ◽  
Patient Response ◽  
Receptor Complexes

289 Background: Gemcitabine, the first-line treatment for pancreatic cancer, has been improved by addition of nab-paclitaxel. However, patient response to this regimen is limited. Oncogenic insulin-like growth factor 1 (IGF-1) and heregulin (HRG) signaling are associated with increased cancer risk and decreased response to anti-metabolites and taxanes. Therefore, we explored MM-141, a novel bispecific antibody that blocks ErbB3 and IGF-1 receptor (IGF-1R) signaling, in combination with nab-paclitaxel and gemcitabine in preclinical models of pancreatic cancer. Methods: Combinations with MM-141, gemcitabine, and nab-paclitaxel were investigated in pancreatic cancer cell lines, in vitro and in vivo. The effects of MM-141, gemcitabine, and nab-paclitaxel on tumor growth and signaling were measured by 3D spheroid growth, ELISA, Western, and mouse xenograft experiments. Results: In vitro studies show that IGF-1 and HRG are potent activators of AKT signaling, leading to increased pancreatic tumor cell proliferation and decreased sensitivity to gemcitabine and nab-paclitaxel. MM-141 inhibits ligand-induced AKT activation, induces IGF-1R and ErbB3 degradation better than a mixture of IGF-1R and ErbB3 antibodies, and sensitizes cells to gemcitabine and nab-paclitaxel, in vitro. In vivo, MM-141 combines favorably with a nab-paclitaxel/gemcitabine regimen, leading to curative outcomes in a subset of treated mice. Conclusions: ErbB3 and IGF-1R co-inhibition is required to inhibit AKT signaling in pancreatic adenocarcinoma cell lines. These receptors are associated with chemoresistance to gemcitabine and nab-paclitaxel, which is abrogated by co-administration with MM-141. MM-141-induced degradation of oncogenic receptor complexes is likely essential to reverse chemoresistance and enhance effects of the nab-paclitaxel/gemcitabine regimen. These data, taken together with wide-spread expression of IGF-1R and ErbB3 in Stage IV pancreatic adenocarcinoma tissue, support clinical exploration of a MM-141/nab-paclitaxel/gemcitabine regimen in frontline metastatic pancreatic cancer. Preparations for a randomized Phase 2 study are underway.

Oligomerization of the extracellular domain of Boss enhances its binding to the Sevenless receptor and its antagonistic effect on R7 induction

1998 ◽  
Vol 111 (6) ◽  
pp. 737-747 ◽  
Author(s):  
E.A. Sevrioukov ◽  
J.H. Walenta ◽  
A. Sunio ◽  
M. Phistry ◽  
H. Kramer
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Compound Eye ◽  
Transmembrane Domain ◽  
Extracellular Domain ◽  
Antagonistic Effect ◽  
Lac Repressor ◽  
Receptor Complexes

In the developing compound eye of Drosophila, neuronal differentiation of the R7 photoreceptor cell is induced by the interaction of the receptor tyrosine kinase Sevenless with its ligand Bride of sevenless (Boss), which is expressed on the neighboring R8 cell. Boss is an unusual ligand of a receptor tyrosine kinase: it is composed of a large extracellular domain, a transmembrane domain with seven membrane-spanning segments and a cytoplasmic tail. Expression of a monomeric, secreted form of the extracellular domain of Boss is not sufficient for Sevenless activation, and instead acts as a weak antagonist. Because oligomerization appears to be a critical step in the activation of receptor tyrosine kinases, we used oligomerized forms of the Boss extracellular domain to test their ability to bind to Sevenless in vivo and restore R7 induction in vivo. Oligomerization was achieved by fusion to the leucine zipper of the yeast transcription factor GCN4 or to the tetramerization helix of Lac repressor. Binding of these multivalent proteins to Sevenless could be detected in vitro by immunoprecipitation of cross-linked ligand/receptor complexes and in vivo by receptor-dependent ligand localization. However, neither R8-specific or ubiquitous expression of multivalent Exboss ligands rescued the boss phenotype. Instead, these ligands acted as competitive inhibitors for wild-type Boss protein and thereby suppressed R7 induction. Therefore the role of the transmembrane or cytoplasmic domains of Boss in the activation of the Sev receptor cannot be replaced by oligomerization.

scholarly journals CHIP Mediates Degradation of Smad Proteins and Potentially Regulates Smad-Induced Transcription

2004 ◽  
Vol 24 (2) ◽  
pp. 856-864 ◽  
Author(s):  
Linyu Li ◽  
Hong Xin ◽  
Xialian Xu ◽  
Mei Huang ◽  
Xinjun Zhang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Transforming Growth Factor Beta ◽  
Mammalian Cells ◽  
Transforming Growth Factor ◽  
Interacting Protein ◽  
Receptor Complexes ◽  
Morphogenetic Protein ◽  
Smad Proteins

ABSTRACT Transforming growth factor beta (TGF-β)/bone morphogenetic protein (BMP) family ligands interact with specific membrane receptor complexes that have serine/threonine kinase activities. The receptor phosphorylation and activation induced by the ligands leads to phosphorylation of the Smad proteins, which translocate to the nucleus, controlling gene expression. Thus, regulation of Smad proteins is a key step in TGF-β/BMP-induced signal transduction. Here we report a novel mechanism of the regulation of SMAD-mediated signaling, by which the Smad1 protein level is controlled through expression of the CHIP protein. CHIP is a U-box-dependent E3 ubiquitin ligase, previously identified as a cochaperon protein. However, we have isolated CHIP as a Smad-interacting protein in a yeast two-hybrid screen using Smad1 as bait. Furthermore we have shown CHIP-Smad interaction using the 35S-labeled CHIP protein, which can interact with glutathione S-transferase (GST)-Smad1 and GST-Smad4 in an in vitro protein-binding assay. The CHIP-Smad interaction has been confirmed in vivo in mammalian cells through coimmunoprecipitation. Interestingly, we demonstrate that the coexpression of Smad1 and Smad4 with the CHIP protein results in the degradation of the Smad proteins through a ubiquitin-mediated process. Consistent with the observation that CHIP induces Smad1 degradation, we further show that the expression of CHIP can inhibit the transcriptional activities of the Smad1/Smad4 complex induced by BMP signals. Intriguingly, pBS/U6/CHIPi, which diminishes CHIP expression, significantly enhanced Smad1/Smad4- or BMPRIB(QD)-induced gene transcription. These results suggest that CHIP can interact with the Smad1/Smad4 proteins and block BMP signal transduction through the ubiquitin-mediated degradation of Smad proteins.

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