Plasma Membrane Is the Primary Site of Localization of the Nonactivated Estrogen Receptor in the Goat Uterus: Hormone Binding Causes Receptor Internalization

Karthikeyan, Narayanan; Thampan, Raghava Varman

doi:10.1006/abbi.1996.0006

Cited by 38 publications

(23 citation statements)

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“…Finally, with the discovery of ER-␤ (Kuiper et al, 1996) we cannot exclude the possibility that the effect of estrogen on ERK activation may occur either via this novel receptor, a proposed membrane-associated estrogen receptor (Pietras and Szego, 1977;Pappas et al, 1995;Karthikeyan and Thampan, 1996), or even an as yet unidentified ER. Thus, it is possible that more than one subtype of the ER could interact with this putative complex.…”

Section: Discussionmentioning

confidence: 99%

Estrogen-Induced Activation of Mitogen-Activated Protein Kinase in Cerebral Cortical Explants: Convergence of Estrogen and Neurotrophin Signaling Pathways

et al. 1999

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We have shown that estrogen elicits a selective enhancement of the growth and differentiation of axons and dendrites (neurites) in the developing CNS. We subsequently demonstrated widespread colocalization of estrogen and neurotrophin receptors (trk) within developing forebrain neurons and reciprocal transcriptional regulation of these receptors by their ligands. Using organotypic explants of the cerebral cortex, we tested the hypothesis that estrogen/neurotrophin receptor coexpression also may result in convergence or cross-coupling of their signaling pathways. Estradiol elicited rapid (within 5-15 min) tyrosine phosphorylation/activation of the mitogen-activated protein (MAP) kinases, ERK1 and ERK2, that persisted for at least 2 hr. This extracellular signal-regulated protein kinase (ERK) activation was inhibited successfully by the MEK1 inhibitor PD98059, but not by the estrogen receptor (ER) antagonist ICI 182,780, and did not appear to result from estradiol-induced activation of trk. Furthermore, we also found that estradiol elicited an increase in B-Raf kinase activity. The latter and subsequent downstream events leading to ERK activation may be a consequence of our documentation of a multimeric complex consisting of, at least, the ER, hsp90, and B-Raf. These novel findings provide an alternative mechanism for some of the estrogen actions in the developing CNS and could explain not only some of the very rapid effects of estrogen but also the ability of estrogen and neurotrophins to regulate the same broad array of cytoskeletal and growth-associated genes involved in neurite growth and differentiation.

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Section: Discussionmentioning

confidence: 99%

Estrogen-Induced Activation of Mitogen-Activated Protein Kinase in Cerebral Cortical Explants: Convergence of Estrogen and Neurotrophin Signaling Pathways

et al. 1999

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“…Glycosylated ER, but not deglycosylated ER, dimerized with ER activation factor. The plasma membrane appears to be the primary site of localization of the glycosylated non-activated ER (Karthikeyan & Thampan 1996). Jiang & Hart (1997) reported a subpopulation of murine, bovine and human ERs that contained O-linked N-acetylglucosamine and the O-glycosylation alternates with O-phosphorylation (Cheng et al 2000).…”

Section: Discussionmentioning

confidence: 99%

Subcellular distribution and glycosylation pattern of androgen receptor from sheep omental adipose tissue

McCann

Mayes²,

Hendricks³

et al. 2001

Journal of Endocrinology

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Sex steroids are known to have an influence on the distribution, metabolism and accretion of adipose tissue. These steroids carry out their function via specific receptors. We have previously reported the presence of oestrogen and progesterone receptors in sheep adipose tissues. In this study, we have tested the subcellular distribution of androgen receptor (AR) in sheep omental adipose tissue. Subcellular fractions -microsomes, plasma membrane and nuclei-cell debris -were isolated by differential and sucrose gradient centrifugation and confirmed by electron microscopy. The AR was determined in each fraction by Western blot analyses. As anticipated, the receptor was found in the cytosolic fraction, but a high concentration was also present in the microsomal fraction, a lesser amount in the plasma membrane fraction, and only a small amount was left in the nuclei-cell debris fraction. Two minor immunostaining bands with approximate molecular weights of 250 and 140 kDa and a major band at 110 kDa were detected in the cytosolic fraction, but only the 110 kDa band was detected in the membrane fractions. A 104 kDa band was observed on occasion and believed to be a degradation product.The cytosolic isoforms were tested for sensitivity to glycosidases. This treatment resulted in a decrease in the amount of the 250 and 140 kDa bands. To substantiate that the 250 and 140 kDa isoforms were glycoproteins, the cytosolic fraction was chromatographed on Concanavalin A-Sepharose. The 110 kDa band was eluted in the 0·4 M KCl salt wash while the 250 and 140 kDa bands were eluted with -methylmannoside. Treatment of the glycoprotein ( -methylmannoside) peak with glycosidases converted the 250 and 140 kDa bands to the 110 kDa band. These data confirm the presence of AR in subcellular fractions of adipose tissue and suggest that it exists in various glycosylated isoforms.

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“…Furthermore, cell membrane-impermeable estrogen (estradiol conjugated to BSA) stimulates MAPK activity (15). A possible explanation for this phenomenon comes from several studies that have reported the existence of plasma membrane-associated ER (16)(17)(18)(19). Activation of MAPK raises the possibility that some or all of the mitogenic activity of estrogen may be mediated through this pathway.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Breast Cancer Susceptibility Gene BRCA2

Lobenhofar¹,

Marks²

2000

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Plasma Membrane Is the Primary Site of Localization of the Nonactivated Estrogen Receptor in the Goat Uterus: Hormone Binding Causes Receptor Internalization

Cited by 38 publications

References 0 publications

Estrogen-Induced Activation of Mitogen-Activated Protein Kinase in Cerebral Cortical Explants: Convergence of Estrogen and Neurotrophin Signaling Pathways

Estrogen-Induced Activation of Mitogen-Activated Protein Kinase in Cerebral Cortical Explants: Convergence of Estrogen and Neurotrophin Signaling Pathways

Subcellular distribution and glycosylation pattern of androgen receptor from sheep omental adipose tissue

Characterization of the Breast Cancer Susceptibility Gene BRCA2

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