title: Rapid nitric oxide-mediated S-nitrosylation of estrogen receptor: regulation of estrogen-dependent gene transcription.
abstract: Nitric oxide (NO) and estrogen receptor (ER) are both important mediators of signal transduction in cardiovascular and reproductive tissues. In this study, we evaluated NO-mediated S-nitrosylation of ER and assessed the effect of this structural modification on transcription-related functions of ER. We have found selective inhibitory effects of NO on specific binding of ER to specific estrogen-responsive elements (ERE) that can be reversed in the presence of the reducing agent, DTT, thus suggesting that S-nitrosylation of thiolate-zinc centers may occur within the ER molecule. Furthermore, we examined inhibitory effects of NO on ER-dependent transcriptional activity by using an ERE-driven reporter gene system. By monitoring biophysical changes in the structure of NO-treated or untreated human recombinant ERalpha,we obtained evidence for the formation of S-nitrosothiols in the ER molecule. In addition, we have detected specific S-nitrosylation of cysteine residues within the ER molecule by immunodetection of S-nitrosocysteine moieties in ER. Collectively, these findings suggest an important physiological role for NO in modification of human ER structure by S-nitrosylation, an effect that leads, in turn, to impaired DNA-binding activity of ER and subsequent blockade of estrogen-dependent gene transcription. Thus, NO-induced S-nitrosylation of ER can occur at cysteine residues that coordinate Zn2+ within the two major DNA-binding Zn-finger domains of ER, resulting in selective inhibition of DNA-binding at specific ERE. This cross-communication between NO and ER may favor activation of rapid (nongenomic) signaling pathways and subsequent modulation of downstream genomic activity.
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
authors.forename: Hermes J
authors.initials: HJ
authors.lastname: Garbán
authors.forename: Diana C
authors.initials: DC
authors.lastname: Márquez-Garbán
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Pietras
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Ignarro
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D002460:Cell Line; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000737:chemistry / Q000378:metabolism; D004967:Estrogens / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D008954:Models, Biological; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D011960:Receptors, Estrogen / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D026403:S-Nitrosothiols / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
chemical_list: D047628:Estrogen Receptor alpha; D004967:Estrogens; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D026403:S-Nitrosothiols; D009569:Nitric Oxide; D004247:DNA; C021315:S-nitrosocysteine; D003545:Cysteine