Summary: Oestrogen receptor
Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.
This is the Wikipedia entry entitled "Estrogen receptor". More...
The Wikipedia text that you see displayed here is a download from Wikipedia. This means that the information we display is a copy of the information from the Wikipedia database. The button next to the article title ("Edit Wikipedia article") takes you to the edit page for the article directly within Wikipedia. You should be aware you are not editing our local copy of this information. Any changes that you make to the Wikipedia article will not be displayed here until we next download the article from Wikipedia. We currently download new content on a nightly basis.
Does Pfam agree with the content of the Wikipedia entry ?
Pfam has chosen to link families to Wikipedia articles. In some case we have created or edited these articles but in many other cases we have not made any direct contribution to the content of the article. The Wikipedia community does monitor edits to try to ensure that (a) the quality of article annotation increases, and (b) vandalism is very quickly dealt with. However, we would like to emphasise that Pfam does not curate the Wikipedia entries and we cannot guarantee the accuracy of the information on the Wikipedia page.
Editing Wikipedia articles
Before you edit for the first time
Wikipedia is a free, online encyclopedia. Although anyone can edit or contribute to an article, Wikipedia has some strong editing guidelines and policies, which promote the Wikipedia standard of style and etiquette. Your edits and contributions are more likely to be accepted (and remain) if they are in accordance with this policy.
You should take a few minutes to view the following pages:
How your contribution will be recorded
Anyone can edit a Wikipedia entry. You can do this either as a new user or you can register with Wikipedia and log on. When you click on the "Edit Wikipedia article" button, your browser will direct you to the edit page for this entry in Wikipedia. If you are a registered user and currently logged in, your changes will be recorded under your Wikipedia user name. However, if you are not a registered user or are not logged on, your changes will be logged under your computer's IP address. This has two main implications. Firstly, as a registered Wikipedia user your edits are more likely seen as valuable contribution (although all edits are open to community scrutiny regardless). Secondly, if you edit under an IP address you may be sharing this IP address with other users. If your IP address has previously been blocked (due to being flagged as a source of 'vandalism') your edits will also be blocked. You can find more information on this and creating a user account at Wikipedia.
If you have problems editing a particular page, contact us at email@example.com and we will try to help.
The community annotation is a new facility of the Pfam web site. If you have problems editing or experience problems with these pages please contact us.
Estrogen receptor Edit Wikipedia article
|estrogen receptor 1 (ER-alpha)|
A dimer of the ligand-binding region of ERα (PDB rendering based on ).
|Alt. symbols||ER-α, NR3A1|
|PDB||1ERE (RCSB PDB PDBe PDBj)|
|Locus||Chr. 6 q24-q27|
|estrogen receptor 2 (ER-beta)|
A dimer of the ligand-binding region of ERβ (PDB rendering based on ).
|Alt. symbols||ER-β, NR3A2|
|PDB||1QKM (RCSB PDB PDBe PDBj)|
|Locus||Chr. 14 q21-q22|
Estrogen receptors are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen (17β-estradiol). Two classes of estrogen receptor exist: ER, which is a member of the nuclear hormone family of intracellular receptors, and GPER (GPR30), which is a member of the rhodopsin-like family of G protein-coupled receptors. This article refers to the former (ER).
Once activated by estrogen, the ER is able to translocate into the nucleus and bind to DNA to regulate the activity of different genes (i.e. it is a DNA-binding transcription factor). However, it also has additional functions independent of DNA binding.
There are two different forms of the estrogen receptor, usually referred to as α and β, each encoded by a separate gene (ESR1 and ESR2, respectively). Hormone-activated estrogen receptors form dimers, and, since the two forms are coexpressed in many cell types, the receptors may form ERα (αα) or ERβ (ββ) homodimers or ERαβ (αβ) heterodimers. Estrogen receptor alpha and beta show significant overall sequence homology, and both are composed of five domains (listed from the N- to C-terminus; amino acid sequence numbers refer to human ER):(A-F domain)
The N-terminal A/B domain is able to transactivate gene transcription in the absence of bound ligand (e.g., the estrogen hormone). While this region is able to activate gene transcription without ligand, this activation is weak and more selective compared to the activation provided by the E domain. The C domain, also known as the DNA-binding domain, binds to estrogen response elements in DNA. The D domain is a hinge region that connects the C and E domains. The E domain contains the ligand binding cavity as well as binding sites for coactivator and corepressor proteins. The E-domain in the presence of bound ligand is able to activate gene transcription. The C-terminal F domain function is not entirely clear and is variable in length.
Due to alternative RNA splicing, several ER isoforms are known to exist. At least three ERalpha and five ERbeta isoforms have been identified. The ERbeta isoforms receptor subtypes can transactivate transcription only when a heterodimer with the functional ERß1 receptor of 59 kDa is formed. The ERß3 receptor was detected at high levels in the testis. The two other ERalpha isoforms are 36 and 46kDa.
Only in fish, but not in humans, an ERgamma receptor has been described.
Both ERs are widely expressed in different tissue types, however there are some notable differences in their expression patterns:
- The ERα is found in endometrium, breast cancer cells, ovarian stromal cells, and the hypothalamus. In males, ERα protein is found in the epithelium of the efferent ducts.
- The expression of the ERβ protein has been documented in ovarian granulosa cells, kidney, brain, bone, heart, lungs, intestinal mucosa, prostate, and endothelial cells.
The ERs are regarded to be cytoplasmic receptors in their unliganded state, but visualization research has shown that a fraction of the ERs resides in the nucleus. The "ERα" primary transcript gives rise to several alternatively spliced variants of unknown function.
Binding and functional selectivity
Different ligands may differ in their affinity for alpha and beta isoforms of the estrogen receptor:
- estradiol binds equally well to both receptors
- estrone, and raloxifene bind preferentially to the alpha receptor
- estriol, and genistein to the beta receptor
Subtype selective estrogen receptor modulators preferentially bind to either the α- or the β-subtype of the receptor. In addition, the different estrogen receptor combinations may respond differently to various ligands, which may translate into tissue selective agonistic and antagonistic effects. The ratio of α- to β- subtype concentration has been proposed to play a role in certain diseases.
The concept of selective estrogen receptor modulators is based on the ability to promote ER interactions with different proteins such as transcriptional coactivator or corepressors. Furthermore, the ratio of coactivator to corepressor protein varies in different tissues. As a consequence, the same ligand may be an agonist in some tissue (where coactivators predominate) while antagonistic in other tissues (where corepressors dominate). Tamoxifen, for example, is an antagonist in breast and is, therefore, used as a breast cancer treatment but an ER agonist in bone (thereby preventing osteoporosis) and a partial agonist in the endometrium (increasing the risk of uterine cancer) .
In the absence of hormone, estrogen receptors are largely located in the cytosol. Hormone binding to the receptor triggers a number of events starting with migration of the receptor from the cytosol into the nucleus, dimerization of the receptor, and subsequent binding of the receptor dimer to specific sequences of DNA known as hormone response elements. The DNA/receptor complex then recruits other proteins that are responsible for the transcription of downstream DNA into mRNA and finally protein that results in a change in cell function. Estrogen receptors also occur within the cell nucleus, and both estrogen receptor subtypes have a DNA-binding domain and can function as transcription factors to regulate the production of proteins.
Direct acetylation of the estrogen receptor alpha at the lysine residues in hinge region by p300 regulates transactivation and hormone sensitivity.
In addition, some ER may associate with cell membranes by attachment to caveolin-1 and form complexes with G proteins, striatin, receptor tyrosine kinases (e.g., EGFR and IGF-1), and non-receptor tyrosine kinases (e.g., Src). Through striatin, some of this membrane bound ER may lead to increased levels of Ca2+ and nitric oxide (NO). Through the receptor tyrosine kinases, signals are sent to the nucleus through the mitogen-activated protein kinase (MAPK/ERK) pathway and phosphoinositide 3-kinase (Pl3K/AKT) pathway. Glycogen synthase kinase-3 (GSK)-3β inhibits transcription by nuclear ER by inhibiting phosphorylation of serine 118 of nuclear ERα. Phosphorylation of GSK-3β removes its inhibitory effect, and this can be achieved by the PI3K/AKT pathway and the MAPK/ERK pathway, via rsk.
Estrogen receptors are over-expressed in around 70% of breast cancer cases, referred to as "ER-positive", and can be demonstrated in such tissues using immunohistochemistry. Two hypotheses have been proposed to explain why this causes tumorigenesis, and the available evidence suggests that both mechanisms contribute:
- First, binding of estrogen to the ER stimulates proliferation of mammary cells, with the resulting increase in cell division and DNA replication, leading to mutations.
- Second, estrogen metabolism produces genotoxic waste.
The result of both processes is disruption of cell cycle, apoptosis and DNA repair, and, therefore, tumour formation. ERα is certainly associated with more differentiated tumours, while evidence that ERβ is involved is controversial. Different versions of the ESR1 gene have been identified (with single-nucleotide polymorphisms) and are associated with different risks of developing breast cancer.
Estrogen and the ERs have also been implicated in breast cancer, ovarian cancer, colon cancer, prostate cancer, and endometrial cancer. Advanced colon cancer is associated with a loss of ERβ, the predominant ER in colon tissue, and colon cancer is treated with ERβ-specific agonists.
Endocrine therapy for breast cancer involves selective estrogen receptor modulators (SERMS), such as tamoxifen, which behave as ER antagonists in breast tissue, or aromatase inhibitors, such as anastrozole. ER status is used to determine sensitivity of breast cancer lesions to tamoxifen and aromatase inhibitors. Another SERM, raloxifene, has been used as a preventive chemotherapy for women judged to have a high risk of developing breast cancer. Another chemotherapeutic anti-estrogen, ICI 182,780 (Faslodex), which acts as a complete antagonist, also promotes degradation of the estrogen receptor.
However, de novo resistance to endocrine therapy undermines the efficacy of using competitive inhibitors like tamoxifen. Hormone deprivation through the use of aromatase inhibitors is also rendered futile. Massively parallel genome sequencing has revealed the common presence of point mutations on ESR1 that are drivers for resistance, and promote the agonist conformation of ERα without the bound ligand. Such constitutive, estrogen-independent activity is driven by specific mutations, such as the D538G or Y537S/C/N mutations, in the ligand binding domain of ESR1 and promote cell proliferation and tumor progression without hormone stimulation.
Studies in female mice have shown that estrogen receptor-alpha declines in the pre-optic hypothalamus as they grow old. Female mice that were given a calorically restricted diet during the majority of their lives maintained higher levels of ERα in the pre-optic hypothalamus than their non-calorically restricted counterparts.
A dramatic demonstration of the importance of estrogens in the regulation of fat deposition comes from transgenic mice that were genetically engineered to lack a functional aromatase gene. These mice have very low levels of estrogen and are obese. Obesity was also observed in estrogen deficient female mice lacking the follicle-stimulating hormone receptor. The effect of low estrogen on increased obesity has been linked to estrogen receptor alpha.
Estrogen receptors were first identified by Elwood V. Jensen at the University of Chicago in 1958, for which Jensen was awarded the Lasker Award. The gene for a second estrogen receptor (ERβ) was identified in 1996 by Kuiper et al. in rat prostate and ovary using degenerate ERalpha primers.
- Dahlman-Wright K, Cavailles V, Fuqua SA, Jordan VC, Katzenellenbogen JA, Korach KS, Maggi A, Muramatsu M, Parker MG, Gustafsson JA (2006). "International Union of Pharmacology. LXIV. Estrogen receptors". Pharmacol. Rev. 58 (4): 773–81. doi:10.1124/pr.58.4.8. PMID 17132854.
- Levin ER (2005). "Integration of the extranuclear and nuclear actions of estrogen". Mol. Endocrinol. 19 (8): 1951–9. doi:10.1210/me.2004-0390. PMC 1249516. PMID 15705661.
- Li X, Huang J, Yi P, Bambara RA, Hilf R, Muyan M (2004). "Single-chain estrogen receptors (ERs) reveal that the ERalpha/beta heterodimer emulates functions of the ERalpha dimer in genomic estrogen signaling pathways". Mol. Cell. Biol. 24 (17): 7681–94. doi:10.1128/MCB.24.17.7681-7694.2004. PMC 506997. PMID 15314175.
- Nilsson S, Mäkelä S, Treuter E, Tujague M, Thomsen J, Andersson G, Enmark E, Pettersson K, Warner M, Gustafsson JA (October 2001). "Mechanisms of estrogen action". Physiol Rev 81 (4): 1535–65. PMID 11581496.
- Leung YK, Mak P, Hassan S, Ho SM (August 2006). "Estrogen receptor (ER)-beta isoforms: a key to understanding ER-beta signaling". Proc Natl Acad Sci USA 103 (35): 13162–7. doi:10.1073/pnas.0605676103. PMC 1552044. PMID 16938840.
- Hawkins MB, Thornton JW, Crews D, Skipper JK, Dotte A, Thomas P (September 2000). "Identification of a third distinct estrogen receptor and reclassification of estrogen receptors in teleosts". Proc Natl Acad Sci USA 97 (20): 10751–6. doi:10.1073/pnas.97.20.10751. PMC 27095. PMID 11005855.
- Couse JF, Lindzey J, Grandien K, Gustafsson JA, Korach KS (November 1997). "Tissue distribution and quantitative analysis of estrogen receptor-alpha (ERalpha) and estrogen receptor-beta (ERbeta) messenger ribonucleic acid in the wild-type and ERalpha-knockout mouse". Endocrinology 138 (11): 4613–21. doi:10.1210/en.138.11.4613. PMID 9348186.
- Yaghmaie F, Saeed O, Garan SA, Freitag W, Timiras PS, Sternberg H (2005). "Caloric restriction reduces cell loss and maintains estrogen receptor-alpha immunoreactivity in the pre-optic hypothalamus of female B6D2F1 mice". Neuro Endocrinol. Lett. 26 (3): 197–203. PMID 15990721.
- Hess RA (2003). "Estrogen in the adult male reproductive tract: A review". Reproductive Biology and Endocrinology 1 (52): 52. doi:10.1186/1477-7827-1-52. PMC 179885. PMID 12904263.
- Babiker FA, De Windt LJ, van Eickels M, Grohe C, Meyer R, Doevendans PA (2002). "Estrogenic hormone action in the heart: regulatory network and function". Cardiovasc. Res. 53 (3): 709–19. doi:10.1016/S0008-6363(01)00526-0. PMID 11861041.
- Htun H, Holth LT, Walker D, Davie JR, Hager GL (1 February 1999). "Direct visualization of the human estrogen receptor alpha reveals a role for ligand in the nuclear distribution of the receptor". Mol Biol Cell 10 (2): 471–86. doi:10.1091/mbc.10.2.471. PMC 25181. PMID 9950689.
- Pfeffer U, Fecarotta E, Vidali G (15 May 1995). "Coexpression of multiple estrogen receptor variant messenger RNAs in normal and neoplastic breast tissues and in MCF-7 cells". Cancer Res 55 (10): 2158–65. PMID 7743517.
- Ascenzi P, Bocedi A, Marino M (August 2006). "Structure-function relationship of estrogen receptor alpha and beta: impact on human health". Mol Aspects Med 27 (4): 299–402. doi:10.1016/j.mam.2006.07.001. PMID 16914190.
- Bourguet W, Germain P, Gronemeyer H (October 2000). "Nuclear receptor ligand-binding domains: three-dimensional structures, molecular interactions and pharmacological implications". Trends Pharmacol Sci 21 (10): 381–8. doi:10.1016/S0165-6147(00)01548-0. PMID 11050318.
- Kansra S, Yamagata S, Sneade L, Foster L, Ben-Jonathan N (2005). "Differential effects of estrogen receptor antagonists on pituitary lactotroph proliferation and prolactin release". Mol. Cell. Endocrinol. 239 (1-2): 27–36. doi:10.1016/j.mce.2005.04.008. PMID 15950373.
- Bakas P, Liapis A, Vlahopoulos S, Giner M, Logotheti S, Creatsas G, Meligova AK, Alexis MN, Zoumpourlis V (December 2007). "Estrogen receptor alpha and beta in uterine fibroids: a basis for altered estrogen responsiveness". Fertil. Steril. 90 (5): 1878–85. doi:10.1016/j.fertnstert.2007.09.019. PMID 18166184.
- Shang Y, Brown M (2002). "Molecular determinants for the tissue specificity of SERMs". Science 295 (5564): 2465–8. doi:10.1126/science.1068537. PMID 11923541.
- Deroo BJ, Korach KS (2006). "Estrogen receptors and human disease". J. Clin. Invest. 116 (3): 561–7. doi:10.1172/JCI27987. PMC 2373424. PMID 16511588.
- Wang C, Fu M, Angeletti RH, Siconolfi-Baez L, Reutens AT, Albanese C, Lisanti MP, Katzenellenbogen BS, Kato S, Hopp T, Fuqua SA, Lopez GN, Kushner PJ, Pestell RG (25 May 2001). "Direct acetylation of the estrogen receptor alpha hinge region by p300 regulates transactivation and hormone sensitivity.". J Biol Chem. 276 (21): 18375–83. doi:10.1074/jbc.m100800200. PMID 11279135.
- Zivadinovic D, Gametchu B, Watson CS (2005). "Membrane estrogen receptor-alpha levels in MCF-7 breast cancer cells predict cAMP and proliferation responses". Breast Cancer Res. 7 (1): R101–12. doi:10.1186/bcr958. PMC 1064104. PMID 15642158.
- Björnström L, Sjöberg M (2004). "Estrogen receptor-dependent activation of AP-1 via non-genomic signalling". Nucl Recept 2 (1): 3. doi:10.1186/1478-1336-2-3. PMC 434532. PMID 15196329.
- Lu Q, Pallas DC, Surks HK, Baur WE, Mendelsohn ME, Karas RH (2004). "Striatin assembles a membrane signaling complex necessary for rapid, nongenomic activation of endothelial NO synthase by estrogen receptor alpha". Proc. Natl. Acad. Sci. U.S.A. 101 (49): 17126–31. doi:10.1073/pnas.0407492101. PMC 534607. PMID 15569929.
- Kato S, Endoh H, Masuhiro Y, Kitamoto T, Uchiyama S, Sasaki H, Masushige S, Gotoh Y, Nishida E, Kawashima H, Metzger D, Chambon P (1995). "Activation of the estrogen receptor through phosphorylation by mitogen-activated protein kinase". Science 270 (5241): 1491–4. doi:10.1126/science.270.5241.1491. PMID 7491495.
- Prossnitz ER, Arterburn JB, Sklar LA (2007). "GPR30: A G protein-coupled receptor for estrogen". Mol. Cell. Endocrinol. 265-266: 138–42. doi:10.1016/j.mce.2006.12.010. PMC 1847610. PMID 17222505.
- Otto C, Rohde-Schulz B, Schwarz G, Fuchs I, Klewer M, Brittain D, Langer G, Bader B, Prelle K, Nubbemeyer R, Fritzemeier KH (2008). "G protein-coupled receptor 30 localizes to the endoplasmic reticulum and is not activated by estradiol.". Endocrinology. 149 (10): 4846–56. doi:10.1210/en.2008-0269. PMID 18566127.
- Harris HA, Albert LM, Leathurby Y, Malamas MS, Mewshaw RE, Miller CP, Kharode YP, Marzolf J, Komm BS, Winneker RC, Frail DE, Henderson RA, Zhu Y, Keith JC (2003). "Evaluation of an estrogen receptor-beta agonist in animal models of human disease". Endocrinology 144 (10): 4241–9. doi:10.1210/en.2003-0550. PMID 14500559.
- Clemons M, Danson S, Howell A (2002). "Tamoxifen ("Nolvadex"): a review". Cancer Treat. Rev. 28 (4): 165–80. doi:10.1016/s0305-7372(02)00036-1. PMID 12363457.
- Fabian CJ, Kimler BF (2005). "Selective estrogen-receptor modulators for primary prevention of breast cancer". J. Clin. Oncol. 23 (8): 1644–55. doi:10.1200/JCO.2005.11.005. PMID 15755972.
- Oesterreich S, Davidson NE (2013). "The search for ESR1 mutations in breast cancer". Nature Genetics 45 (12): 1415–6. doi:10.1038/ng.2831. PMID 24270445.
- Li S, Shen D, Shao J, Crowder R, Liu W, Prat A, He X, Liu S, Hoog J, Lu C, Ding L, Griffith OL, Miller C, Larson D, Fulton RS, Harrison M, Mooney T, McMichael JF, Luo J, Tao Y, Goncalves R, Schlosberg C, Hiken JF, Saied L, Sanchez C, Giuntoli T, Bumb C, Cooper C, Kitchens RT, Lin A, Phommaly C, Davies SR, Zhang J, Kavuri MS, McEachern D, Dong YY, Ma C, Pluard T, Naughton M, Bose R, Suresh R, McDowell R, Michel L, Aft R, Gillanders W, DeSchryver K, Wilson RK, Wang S, Mills GB, Gonzalez-Angulo A, Edwards JR, Maher C, Perou CM, Mardis ER, Ellis MJ (2013). "Endocrine-therapy-resistant ESR1 variants revealed by genomic characterization of breast-cancer-derived xenografts". Cell Reports 4 (6): 1116–30. doi:10.1016/j.celrep.2013.08.022. PMC 3881975. PMID 24055055.
- Darabi M, Ani M, Panjehpour M, Rabbani M, Movahedian A, Zarean E (2011). "Effect of estrogen receptor β A1730G polymorphism on ABCA1 gene expression response to postmenopausal hormone replacement therapy". Genet Test Mol Biomarkers 15 (1-2): 11–5. doi:10.1089/gtmb.2010.0106. PMID 21117950.
- Hewitt KN, Boon WC, Murata Y, Jones ME, Simpson ER (2003). "The aromatase knockout mouse presents with a sexually dimorphic disruption to cholesterol homeostasis". Endocrinology 144 (9): 3895–903. doi:10.1210/en.2003-0244. PMID 12933663.
- Danilovich N, Babu PS, Xing W, Gerdes M, Krishnamurthy H, Sairam MR (2000). "Estrogen deficiency, obesity, and skeletal abnormalities in follicle-stimulating hormone receptor knockout (FORKO) female mice". Endocrinology 141 (11): 4295–308. doi:10.1210/en.141.11.4295. PMID 11089565.
- Ohlsson C, Hellberg N, Parini P, Vidal O, Bohlooly-Y M, Bohlooly M, Rudling M, Lindberg MK, Warner M, Angelin B, Gustafsson JA (2000). "Obesity and disturbed lipoprotein profile in estrogen receptor-alpha-deficient male mice". Biochem. Biophys. Res. Commun. 278 (3): 640–5. doi:10.1006/bbrc.2000.3827. PMID 11095962.
- Jensen EV, Jordan VC (1 June 2003). "The estrogen receptor: a model for molecular medicine" (abstract). Clin. Cancer Res. 9 (6): 1980–9. PMID 12796359.
- Jensen E (2011). "A Conversation with Elwood Jensen.". Annu Rev Physiol 74: 1–11. doi:10.1146/annurev-physiol-020911-153327. PMID 21888507.
- David Bracey, 2004 "UC Scientist Wins 'American Nobel' Research Award." University of Cincinnati press release.
- Kuiper GG, Enmark E, Pelto-Huikko M, Nilsson S, Gustafsson JA (1996). "Cloning of a novel receptor expressed in rat prostate and ovary". Proc. Natl. Acad. Sci. U.S.A. 93 (12): 5925–30. doi:10.1073/pnas.93.12.5925. PMC 39164. PMID 8650195.
- Estrogen Receptors at the US National Library of Medicine Medical Subject Headings (MeSH)
- David S. Goodsell (2003-09-01). "Estrogen Receptor". Protein Data Bank, Research Collaboratory for Structural Bioinformatics (RCSB). Retrieved 2008-03-15.
This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.
Oestrogen receptor Provide feedback
No Pfam abstract.
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR001292
Steroid or nuclear hormone receptors (4A nuclear receptor, NRs) constitute an important superfamily of transcription regulators that are involved in widely diverse physiological functions, including control of embryonic development, cell differentiation and homeostasis. Members of the superfamily include the steroid hormone receptors and receptors for thyroid hormone, retinoids, 1,25-dihydroxy-vitamin D3 and a variety of other ligands [PUBMED:14747695]. The proteins function as dimeric molecules in nuclei to regulate the transcription of target genes in a ligand-responsive manner [PUBMED:7899080, PUBMED:8165128]. In addition to C-terminal ligand-binding domains, these nuclear receptors contain a highly-conserved, N-terminal zinc-finger that mediates specific binding to target DNA sequences, termed ligand-responsive elements. In the absence of ligand, steroid hormone receptors are thought to be weakly associated with nuclear components; hormone binding greatly increases receptor affinity.
NRs are extremely important in medical research, a large number of them being implicated in diseases such as cancer, diabetes, hormone resistance syndromes, etc. While several NRs act as ligand-inducible transcription factors, many do not yet have a defined ligand and are accordingly termed 'orphan' receptors. During the last decade, more than 300 NRs have been described, many of which are orphans, which cannot easily be named due to current nomenclature confusions in the literature. However, a new system has recently been introduced in an attempt to rationalise the increasingly complex set of names used to describe superfamily members.
The oestrogen receptors (ERs) are steroid or nuclear hormone receptors that act as transcription regulators involved in diverse physiological functions. Oestrogen receptors function as dimeric molecules in nuclei to regulate the transcription of target genes in a ligand-responsive manner. The ER consists of three functional and structural domains: an N-terminal modulatory domain, a highly conserved DNA-binding domain that recognises specific sequences (INTERPRO), and a C-terminal ligand-binding domain (INTERPRO).
The N-terminal modulatory domain spans the first 180 residues and contains the activation function 1 (AF1) region. Nuclear receptors differ considerably with respect to AF1 activity and regulation, as it is a poorly conserved region [PUBMED:15831449]. There is another activation function region, namely AF2, which resides in the C-terminal end of the ligand-binding domain. Transcription activation is facilitated by both AF1 and AF2, which appear to act synergistically in the ER complex [PUBMED:15728727, PUBMED:14612550]. For example, the ER can recruit TIF2 (transcription intermediary factor 2) via the AF1 and AF2 regions, whose synergistic action results in the activation of transcription.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||nucleus (GO:0005634)|
|Molecular function||DNA binding (GO:0003677)|
|estrogen receptor activity (GO:0030284)|
|steroid binding (GO:0005496)|
|Biological process||regulation of transcription, DNA-dependent (GO:0006355)|
|steroid hormone mediated signaling pathway (GO:0043401)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
The graphic that is shown by default represents the longest sequence with a given architecture. Each row contains the following information:
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- a link to the page in the Pfam site showing information about the sequence that the graphic describes
- the UniProt description of the protein sequence
- the number of residues in the sequence
- the Pfam graphic itself.
Note that you can see the family page for a particular domain by clicking on the graphic. You can also choose to see all sequences which have a given architecture by clicking on the Show link in each row.
Finally, because some families can be found in a very large number of architectures, we load only the first fifty architectures by default. If you want to see more architectures, click the button at the bottom of the page to load the next set.
Loading domain graphics...
We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...
There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the NCBI sequence database using the family HMM
- alignment generated by searching the metagenomics sequence database using the family HMM
You can see the alignments as HTML or in three different sequence viewers:
- a Java applet developed at the University of Dundee. You will need Java installed before running jalview
- an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
- an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
- Pfam viewer
- an HTML-based viewer that uses DAS to retrieve alignment fragments on request
You can download (or view in your browser) a text representation of a Pfam alignment in various formats:
You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.
You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.
We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.
You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.
MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.
HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...
If you find these logos useful in your own work, please consider citing the following article:
This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.
Note: You can also download the data file for the tree.
Curation and family details
This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.
|Author:||Mian N, Bateman A|
|Number in seed:||11|
|Number in full:||220|
|Average length of the domain:||120.80 aa|
|Average identity of full alignment:||46 %|
|Average coverage of the sequence by the domain:||25.14 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||10|
|Download:||download the raw HMM for this family|
Weight segments by...
Change the size of the sunburst
selected sequences to HMM
a FASTA-format file
- 0 sequences
- 0 species
This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the More....
This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.
How the sunburst is generated
The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.
In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:
Colouring and labels
Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.
As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.
Anomalies in the taxonomy tree
There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.
Missing taxonomic levels
Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.
Unmapped species names
The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.
So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".
Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.
Too many species/sequences
For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.
The tree shows the occurrence of this domain across different species. More...
We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.
Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.
If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.
For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.
We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.
Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.
We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.
You can use the tree controls to manipulate how the interactive tree is displayed:
- show/hide the summary boxes
- highlight species that are represented in the seed alignment
- expand/collapse the tree or expand it to a given depth
- select a sub-tree or a set of species within the tree and view them graphically or as an alignment
- save a plain text representation of the tree
Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.