View source for GroES

{{Short description|Protein}}
{{cs1 config|name-list-style=vanc}}
{{redirect|Groes|the lost village in Wales|Groes, Port Talbot}}
{{Infobox_gene}}
{{Infobox protein family
| Symbol = Cpn10
| Name = Cpn10
| image = PDB 1g31 EBI.jpg
| width = 
| caption = gp31 co-chaperonin from bacteriophage t4
| Pfam = PF00166
| Pfam_clan = CL0296 
| InterPro = IPR020818
| SMART = 
| PROSITE = PDOC00576
| MEROPS = 
| SCOP = 1lep
| TCDB = 
| OPM family = 
| OPM protein = 
| CAZy = 
| CDD = 
}}
'''Heat shock 10 kDa protein 1''' ('''Hsp10'''), also known as '''chaperonin 10''' ('''cpn10''') or '''early-pregnancy factor''' ('''EPF'''), is a [[protein]] that in humans is encoded by the ''HSPE1'' [[gene]].  The homolog in ''[[Escherichia coli|E. coli]]'' is '''GroES''' that is a [[chaperonin]] which usually works in conjunction with [[GroEL]].<ref name="entrez">{{cite web | title = Entrez Gene: HSPE1 heat shock 10kDa protein 1 (chaperonin 10)| url = https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=ShowDetailView&TermToSearch=3336}}</ref>

== Structure and function ==

GroES exists as a ring-shaped [[oligomer]] of between six and eight identical subunits, while the 60 kDa chaperonin (cpn60, or groEL in bacteria) forms a [[secondary structure|structure]] comprising 2 stacked rings, each ring containing 7 identical [[protein subunit|subunits]].<ref name="pmid2897629">{{cite journal | vauthors = Hemmingsen SM, Woolford C, van der Vies SM, Tilly K, Dennis DT, Georgopoulos CP, Hendrix RW, Ellis RJ | title = Homologous plant and bacterial proteins chaperone oligomeric protein assembly | journal = Nature | volume = 333 | issue = 6171 | pages = 330–4  | date = May 1988 | pmid = 2897629 | doi = 10.1038/333330a0 | bibcode = 1988Natur.333..330H | s2cid = 4325057 }}</ref> These ring structures assemble by self-stimulation in the presence of Mg<sup>2+</sup>-ATP. The central cavity of the cylindrical cpn60 tetradecamer provides an isolated environment for [[protein folding]] whilst cpn-10 [[Molecular binding|bind]]s to cpn-60 and synchronizes the release of the [[protein folding|folded]] protein in an Mg<sup>2+</sup>-ATP dependent manner.<ref name="pmid1350777">{{cite journal | vauthors = Schmidt A, Schiesswohl M, Völker U, Hecker M, Schumann W | title = Cloning, sequencing, mapping, and transcriptional analysis of the groESL operon from Bacillus subtilis | journal = J. Bacteriol. | volume = 174 | issue = 12 | pages = 3993–9  | date = June 1992 | pmid = 1350777 | pmc = 206108 | doi =  10.1128/jb.174.12.3993-3999.1992}}</ref> The [[Molecular binding|binding]] of cpn10 to cpn60 [[Enzyme inhibitor|inhibits]] the weak ATPase activity of cpn60.

''[[Escherichia coli]]'' GroES has also been shown to bind [[Adenosine triphosphate|ATP]] cooperatively, and with an affinity comparable to that of GroEL.<ref name="pmid7901771">{{cite journal | vauthors = Martin J, Geromanos S, Tempst P, Hartl FU | title = Identification of nucleotide-binding regions in the chaperonin proteins GroEL and GroES | journal = Nature | volume = 366 | issue = 6452 | pages = 279–82  | date = November 1993 | pmid = 7901771 | doi = 10.1038/366279a0 | bibcode = 1993Natur.366..279M | s2cid = 4243962 }}</ref> Each GroEL subunit contains three [[structurally]] distinct domains: an apical, an intermediate and an equatorial domain. The apical domain contains the [[binding site]]s for both GroES and the unfolded protein substrate. The equatorial domain contains the ATP-binding site and most of the oligomeric contacts. The intermediate domain links the apical and equatorial [[protein domain|domains]] and transfers [[allosteric]] information between them. The GroEL oligomer is a tetradecamer, cylindrically shaped, that is organised in two heptameric rings stacked back to back. Each GroEL ring contains a central cavity, known as the `[[Anfinsen cage]]', that provides an isolated environment for protein folding. The identical 10 kDa subunits of GroES form a dome-like heptameric oligomer in solution. ATP binding to GroES may be important in charging the seven subunits of the interacting GroEL ring with ATP, to facilitate cooperative ATP binding and [[hydrolysis]] for substrate protein release.

== Interactions ==

GroES has been shown to [[Protein-protein interaction|interact]] with [[GroEL]].<ref name="pmid10205158">{{cite journal | vauthors = Samali A, Cai J, Zhivotovsky B, Jones DP, Orrenius S | title = Presence of a pre-apoptotic complex of pro-caspase-3, Hsp60 and Hsp10 in the mitochondrial fraction of jurkat cells | journal = EMBO J. | volume = 18 | issue = 8 | pages = 2040–8  | date = April 1999 | pmid = 10205158 | pmc = 1171288 | doi = 10.1093/emboj/18.8.2040 }}</ref><ref name="pmid12387818">{{cite journal | vauthors = Lee KH, Kim HS, Jeong HS, Lee YS | title = Chaperonin GroESL mediates the protein folding of human liver mitochondrial aldehyde dehydrogenase in Escherichia coli | journal = Biochem. Biophys. Res. Commun. | volume = 298 | issue = 2 | pages = 216–24  | date = October 2002 | pmid = 12387818 | doi = 10.1016/S0006-291X(02)02423-3 }}</ref>

==Detection==
Early pregnancy factor is tested for [[rosette inhibition assay]].  EPF is present in the maternal serum ([[blood plasma]]) shortly after fertilization; EPF is also present in [[cervix|cervical mucus]]
<ref>{{cite journal | vauthors = Cheng SJ, Zheng ZQ | title = Early pregnancy factor in cervical mucus of pregnant women | journal = American Journal of Reproductive Immunology | volume = 51 | issue = 2 | pages = 102–5 | date = Feb 2004 | pmid = 14748834 | doi = 10.1046/j.8755-8920.2003.00136.x | s2cid = 40837910 | doi-access = free }}</ref> and in [[amniotic fluid]].<ref>{{cite journal | vauthors = Zheng ZQ, Qin ZH, Ma AY, Qiao CX, Wang H | title = Detection of early pregnancy factor-like activity in human amniotic fluid | journal = American Journal of Reproductive Immunology | volume = 22 | issue = 1–2 | pages = 9–11 | year = 1990 | pmid = 2346595 | doi = 10.1111/j.1600-0897.1990.tb01025.x | s2cid = 85106990 }}</ref>

EPF may be detected in   sheep within 72 hours of mating,<ref name="sheep1979">{{cite journal | vauthors = Morton H, Clunie GJ, Shaw FD | title = A test for early pregnancy in sheep | journal = Research in Veterinary Science | volume = 26 | issue = 2 | pages = 261–2 | date = Mar 1979 | pmid = 262615 | doi = 10.1016/S0034-5288(18)32933-3 }}</ref> in mice within 24 hours of mating,<ref name="mice">{{cite journal | vauthors = Cavanagh AC, Morton H, Rolfe BE, Gidley-Baird AA | title = Ovum factor: a first signal of pregnancy? | journal = American Journal of Reproductive Immunology | volume = 2 | issue = 2 | pages = 97–101 | date = Apr 1982 | pmid = 7102890 | doi = 10.1111/j.1600-0897.1982.tb00093.x | s2cid = 9624692 }}</ref> and in samples from media surrounding human embryos fertilized [[in vitro]] within 48 hours of fertilization<ref>{{cite journal | vauthors = Smart YC, Cripps AW, Clancy RL, Roberts TK, Lopata A, Shutt DA | title = Detection of an immunosuppressive factor in human preimplantation embryo cultures | journal = The Medical Journal of Australia | volume = 1 | issue = 2 | pages = 78–9 | date = Jan 1981 | doi = 10.5694/j.1326-5377.1981.tb135326.x | pmid = 7231254 | s2cid = 12267649 }}</ref> (although another study failed to duplicate this finding for ''in vitro'' embryos).<ref name="origin">{{cite journal | vauthors = Nahhas F, Barnea E | title = Human embryonic origin early pregnancy factor before and after implantation | journal = American Journal of Reproductive Immunology | volume = 22 | issue = 3–4 | pages = 105–8 | year = 1990 | pmid = 2375830 | doi = 10.1111/j.1600-0897.1990.tb00651.x | s2cid = 21055879 }}</ref>  EPF has been detected as soon as within six hours of mating.<ref name="immuno1980">{{cite journal | vauthors = Shaw FD, Morton H | title = The immunological approach to pregnancy diagnosis: a review | journal = The Veterinary Record | volume = 106 | issue = 12 | pages = 268–70 | date = Mar 1980 | pmid = 6966439 | doi = 10.1136/vr.106.12.268 | doi-broken-date = 12 July 2025 | s2cid = 45876497 }}</ref>

Because the [[rosette inhibition assay]] for EPF is indirect, substances that have similar effects may confound the test. [[Pig semen]], like EPF, has been shown to inhibit rosette formation – the rosette inhibition test was positive for one day in sows mated with a vasectomized boar, but not in sows similarly stimulated without semen exposure.<ref>{{cite journal | vauthors = Koch E, Ellendorff F | title = Detection of activity similar to that of early pregnancy factor after mating sows with a vasectomized boar | journal = Journal of Reproduction and Fertility | volume = 74 | issue = 1 | pages = 39–46 | date = May 1985 | pmid = 4020773 | doi = 10.1530/jrf.0.0740039 | doi-access =  }}</ref>  A number of studies in the years after the discovery of EPF were unable to reproduce the consistent detection of EPF in post-conception females, and the validity of the discovery experiments was questioned.<ref name="criticism">{{cite journal | vauthors = Chard T, Grudzinskas JG | title = Early pregnancy factor | journal = Biological Research in Pregnancy and Perinatology | volume = 8 | issue = 2 2D Half | pages = 53–6 | year = 1987 | pmid = 3322417 }}</ref>  However, progress in characterization of EPF has been made and its existence is well-accepted in the scientific community.<ref name="composition">{{cite journal | vauthors = Di Trapani G, Orosco C, Perkins A, Clarke F | title = Isolation from human placental extracts of a preparation possessing 'early pregnancy factor' activity and identification of the polypeptide components | journal = Human Reproduction | volume = 6 | issue = 3 | pages = 450–7 | date = Mar 1991 | pmid = 1955557 | doi = 10.1093/oxfordjournals.humrep.a137357 }}</ref><ref>{{cite journal | vauthors = Cavanagh AC | title = Identification of early pregnancy factor as chaperonin 10: implications for understanding its role | journal = Reviews of Reproduction | volume = 1 | issue = 1 | pages = 28–32 | date = Jan 1996 | pmid = 9414435 | doi = 10.1530/ror.0.0010028 }}</ref>

== Origin ==

Early embryos are not believed to directly produce EPF. Rather, embryos are believed to produce some other chemical that induces the maternal system to create EPF.<ref>{{cite journal | vauthors = Orozco C, Perkins T, Clarke FM | title = Platelet-activating factor induces the expression of early pregnancy factor activity in female mice | journal = Journal of Reproduction and Fertility | volume = 78 | issue = 2 | pages = 549–55 | date = Nov 1986 | pmid = 3806515 | doi = 10.1530/jrf.0.0780549 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Roberts TK, Adamson LM, Smart YC, Stanger JD, Murdoch RN | title = An evaluation of peripheral blood platelet enumeration as a monitor of fertilization and early pregnancy | journal = Fertility and Sterility | volume = 47 | issue = 5 | pages = 848–54 | date = May 1987 | pmid = 3569561 | doi = 10.1016/S0015-0282(16)59177-8 }}</ref><ref>{{cite journal | vauthors = Sueoka K, Dharmarajan AM, Miyazaki T, Atlas SJ, Wallach EE | title = Platelet activating factor-induced early pregnancy factor activity from the perfused rabbit ovary and oviduct | journal = American Journal of Obstetrics and Gynecology | volume = 159 | issue = 6 | pages = 1580–4 | date = Dec 1988 | pmid = 3207134 | doi = 10.1016/0002-9378(88)90598-4 }}</ref><ref>{{cite journal | vauthors = Cavanagh AC, Morton H, Athanasas-Platsis S, Quinn KA, Rolfe BE | title = Identification of a putative inhibitor of early pregnancy factor in mice | journal = Journal of Reproduction and Fertility | volume = 91 | issue = 1 | pages = 239–48 | date = Jan 1991 | pmid = 1995852 | doi = 10.1530/jrf.0.0910239 | citeseerx = 10.1.1.578.5819 }}</ref><ref>{{cite journal | vauthors = Cavanagh AC, Rolfe BE, Athanasas-Platsis S, Quinn KA, Morton H | title = Relationship between early pregnancy factor, mouse embryo-conditioned medium and platelet-activating factor | journal = Journal of Reproduction and Fertility | volume = 93 | issue = 2 | pages = 355–65 | date = Nov 1991 | pmid = 1787455 | doi = 10.1530/jrf.0.0930355 | doi-access = free }}</ref> After implantation, EPF may be produced by the conceptus directly.<ref name="origin" />

EPF is an immunosuppressant. Along with other substances associated with early embryos, EPF  is believed to play a role in preventing the [[immune system]] of the pregnant female from attacking the embryo.<ref name="immuno1980" /><ref>{{cite journal | vauthors = Bose R, Cheng H, Sabbadini E, McCoshen J, MaHadevan MM, Fleetham J | title = Purified human early pregnancy factor from preimplantation embryo possesses immunosuppresive properties | journal = American Journal of Obstetrics and Gynecology | volume = 160 | issue = 4 | pages = 954–60 | date = Apr 1989 | pmid = 2712125 | doi = 10.1016/0002-9378(89)90316-5 }}</ref> Injecting anti-EPF antibodies into mice after mating significantly {{quantify|date=August 2008}} reduced the number of successful pregnancies and number of pups;<ref>{{cite journal | vauthors = Igarashi S | title = [Significance of early pregnancy factor (EPF) on reproductive immunology] | journal = Nihon Sanka Fujinka Gakkai Zasshi | volume = 39 | issue = 2 | pages = 189–94 | date = Feb 1987 | pmid = 2950188 }}</ref><ref>{{cite journal | vauthors = Athanasas-Platsis S, Quinn KA, Wong TY, Rolfe BE, Cavanagh AC, Morton H | title = Passive immunization of pregnant mice against early pregnancy factor causes loss of embryonic viability | journal = Journal of Reproduction and Fertility | volume = 87 | issue = 2 | pages = 495–502 | date = Nov 1989 | pmid = 2600905 | doi = 10.1530/jrf.0.0870495 | doi-access = free }}</ref> no effect on growth was seen when mice embryos were cultured in media containing anti-EPF antibodies.<ref>{{cite journal | vauthors = Athanasas-Platsis S, Morton H, Dunglison GF, Kaye PL | title = Antibodies to early pregnancy factor retard embryonic development in mice in vivo | journal = Journal of Reproduction and Fertility | volume = 92 | issue = 2 | pages = 443–51 | date = Jul 1991 | pmid = 1886100 | doi = 10.1530/jrf.0.0920443 | doi-access = free }}</ref>  While some actions of EPF are the same in all mammals (namely rosette inhibition), other immunosuppressant mechanism vary between species.<ref>{{cite journal | vauthors = Rolfe BE, Cavanagh AC, Quinn KA, Morton H | title = Identification of two suppressor factors induced by early pregnancy factor | journal = Clinical and Experimental Immunology | volume = 73 | issue = 2 | pages = 219–25 | date = Aug 1988 | pmid = 3180511 | pmc = 1541604 }}</ref>

In mice, EPF levels are high in early pregnancy, but on day 15 decline to levels found in non-pregnant mice.<ref>{{cite journal | vauthors = Takimoto Y, Hishinuma M, Takahashi Y, Kanagawa H | title = Detection of early pregnancy factor in superovulated mice | journal = Nihon Juigaku Zasshi. The Japanese Journal of Veterinary Science | volume = 51 | issue = 5 | pages = 879–85 | date = Oct 1989 | pmid = 2607739 | doi = 10.1292/jvms1939.51.879 | doi-access = free }}</ref> In humans, EPF levels are high for about the first twenty weeks, then decline, becoming undetectable within eight weeks of [[childbirth|delivery]].<ref>{{cite journal | vauthors = Qin ZH, Zheng ZQ | title = Detection of early pregnancy factor in human sera | journal = American Journal of Reproductive Immunology and Microbiology | volume = 13 | issue = 1 | pages = 15–8 | date = Jan 1987 | pmid = 2436493 | doi=10.1111/j.1600-0897.1987.tb00082.x}}</ref><ref>{{cite journal | vauthors = Wang HN, Zheng ZQ | title = Detection of early pregnancy factor in fetal sera | journal = American Journal of Reproductive Immunology | volume = 23 | issue = 3 | pages = 69–72 | date = Jul 1990 | pmid = 2257053 | doi = 10.1111/j.1600-0897.1990.tb00674.x | s2cid = 221409934 }}</ref>

== Clinical utility ==

=== Pregnancy testing ===

It has been suggested that EPF could be used as a marker for a very [[early pregnancy test]], and as a way to monitor the viability of ongoing pregnancies in livestock.<ref name="sheep1979" />  Interest in EPF for this purpose has continued,<ref>{{cite journal | vauthors = Sakonju I, Enomoto S, Kamimura S, Hamana K | title = Monitoring bovine embryo viability with early pregnancy factor | journal = The Journal of Veterinary Medical Science | volume = 55 | issue = 2 | pages = 271–4 | date = Apr 1993 | pmid = 8513008 | doi=10.1292/jvms.55.271| doi-access = free }}</ref> although current test methods have not proved sufficiently accurate for the requirements of livestock management.<ref name="pig">{{cite journal | vauthors = Greco CR, Vivas AB, Bosch RA | title = [Evaluation of the method for early pregnancy factor detection (EPF) in swine. Significance in early pregnancy diagnosis] | journal = Acta Physiologica, Pharmacologica et Therapeutica Latinoamericana | volume = 42 | issue = 1 | pages = 43–50 | year = 1992 | pmid = 1294272 }}</ref><ref>{{cite journal | vauthors = Sasser RG, Ruder CA | title = Detection of early pregnancy in domestic ruminants | journal = Journal of Reproduction and Fertility. Supplement | volume = 34 | pages = 261–71 | year = 1987 | pmid = 3305923 }}</ref><ref>{{cite journal | vauthors = Gandy B, Tucker W, Ryan P, Williams A, Tucker A, Moore A, Godfrey R, Willard S | title = Evaluation of the early conception factor (ECF) test for the detection of nonpregnancy in dairy cattle | journal = Theriogenology | volume = 56 | issue = 4 | pages = 637–47 | date = Sep 2001 | pmid = 11572444 | doi = 10.1016/S0093-691X(01)00595-7 }}</ref><ref>{{cite journal | vauthors = Cordoba MC, Sartori R, Fricke PM | title = Assessment of a commercially available early conception factor (ECF) test for determining pregnancy status of dairy cattle | journal = Journal of Dairy Science | volume = 84 | issue = 8 | pages = 1884–9 | date = Aug 2001 | pmid = 11518314 | doi = 10.3168/jds.S0022-0302(01)74629-2 | doi-access = free }}</ref>

In humans, modern [[pregnancy test]]s detect [[human chorionic gonadotropin]] (hCG).  hCG is not present until after implantation, which occurs six to twelve days after fertilization.<ref>{{cite journal | vauthors = Wilcox AJ, Baird DD, [[Clarice Weinberg|Weinberg CR]] | title = Time of implantation of the conceptus and loss of pregnancy | journal = The New England Journal of Medicine | volume = 340 | issue = 23 | pages = 1796–9 | date = Jun 1999 | pmid = 10362823 | doi = 10.1056/NEJM199906103402304 | doi-access = free }}</ref>  In contrast, EPF is present within hours of fertilization.  While several other pre-implantation signals have been identified, EPF is believed to be the earliest possible marker of pregnancy.<ref name="mice" /><ref>{{cite journal | vauthors = Straube W | title = [Early embryonal signals] | journal = Zentralblatt für Gynäkologie | volume = 111 | issue = 10 | pages = 629–33 | year = 1989 | pmid = 2665388 }}</ref>  The accuracy of EPF as a pregnancy test in humans has been found to be high by several studies.<ref>{{cite journal | vauthors = Smart YC, Roberts TK, Fraser IS, Cripps AW, Clancy RL | title = Validation of the rosette inhibition test for the detection of early pregnancy in women | journal = Fertility and Sterility | volume = 37 | issue = 6 | pages = 779–85 | date = Jun 1982 | pmid = 6177559 | doi = 10.1016/S0015-0282(16)46338-7 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Bessho T, Taira S, Ikuma K, Shigeta M, Koyama K, Isojima S | title = [Detection of early pregnancy factor in the sera of conceived women before nidation] | journal = Nihon Sanka Fujinka Gakkai Zasshi | volume = 36 | issue = 3 | pages = 391–6 | date = Mar 1984 | pmid = 6715922 }}</ref><ref>{{cite journal | vauthors = Straube W, Tiemann U, Loh M, Schütz M | title = Detection of early pregnancy factor (EPF) in pregnant and nonpregnant subjects with the rosette inhibition test | journal = Archives of Gynecology and Obstetrics | volume = 246 | issue = 3 | pages = 181–7 | year = 1989 | pmid = 2619332 | doi = 10.1007/BF00934079 | s2cid = 20531983 }}</ref><ref>{{cite journal | vauthors = Fan XG, Zheng ZQ | title = A study of early pregnancy factor activity in preimplantation | journal = American Journal of Reproductive Immunology | volume = 37 | issue = 5 | pages = 359–64 | date = May 1997 | pmid = 9196793 | doi = 10.1111/j.1600-0897.1997.tb00244.x | s2cid = 71525444 }}</ref>

=== Birth control research ===

EPF may also be used to determine whether pregnancy prevention mechanism of [[birth control]] methods act before or after fertilization.  A 1982 study evaluating EPF levels in women with [[Intrauterine device|IUDs]] concluded that post-fertilization mechanisms contribute significantly{{quantify|date=August 2008}}  to the effectiveness of these devices.<ref>{{cite journal | vauthors = Smart YC, Fraser IS, Clancy RL, Roberts TK, Cripps AW | title = Early pregnancy factor as a monitor for fertilization in women wearing intrauterine devices | journal = Fertility and Sterility | volume = 37 | issue = 2 | pages = 201–4 | date = Feb 1982 | pmid = 6174375 | doi = 10.1016/S0015-0282(16)46039-5 | doi-access = free }}</ref>  However, more recent evidence, such as tubal flushing studies indicates that IUDs work by inhibiting fertilization, acting earlier in the reproductive process than previously thought.<ref name=CT-IUD>{{cite book |author=Grimes, David |year=2007 |chapter=Intrauterine Devices (IUDs) |editor=Hatcher, Robert A. |title=Contraceptive Technology |edition=19th rev. |location=New York |publisher=Ardent Media |isbn=978-0-9664902-0-6 |page=[https://archive.org/details/contraceptivetec00hatc/page/120 120] |display-editors=etal |chapter-url-access=registration |chapter-url=https://archive.org/details/contraceptivetec00hatc/page/120 }}</ref>

For groups that define [[beginning of pregnancy controversy|pregnancy as beginning with fertilization]], birth control methods that have postfertilization mechanisms are regarded as [[abortifacient]].  There is currently contention over whether [[hormonal contraception]] methods have post-fertilization methods, specifically the most popular hormonal method: the [[combined oral contraceptive pill]] (COCP).  The group Pharmacists for Life has called for a large-scale clinical trial to evaluate EPF in women taking COCPs; this would be the most conclusive evidence available to determine whether COCPs have postfertilization mechanisms.<ref>{{cite journal | author =  Lloyd J DuPlantis, Jr | title = Early Pregnancy Factor | publisher = Pharmacists for Life, Intl | year = 2001 | url = http://www.lifeissues.net/writers/dup/dup_01earlypregfacts.html | access-date = 2007-01-01 }}</ref>

=== Infertility and early pregnancy loss ===

EPF is useful when investigating [[embryo loss]] prior to implantation.  One study in healthy human women seeking pregnancy detected fourteen pregnancies with EPF.  Of these, six were [[Spontaneous abortion|lost]] within ten days of [[ovulation]] (43% rate of early conceptus loss).<ref>{{cite journal | vauthors = Smart YC, Fraser IS, Roberts TK, Clancy RL, Cripps AW | title = Fertilization and early pregnancy loss in healthy women attempting conception | journal = Clinical Reproduction and Fertility | volume = 1 | issue = 3 | pages = 177–84 | date = Sep 1982 | pmid = 6196101 }}</ref>

Use of EPF has been proposed to distinguish infertility caused by failure to conceive versus infertility caused by failure to implant.<ref>{{cite journal | vauthors = Mesrogli M, Maas DH, Schneider J | title = [Early abortion rate in sterility patients: early pregnancy factor as a parameter] | journal = Zentralblatt für Gynäkologie | volume = 110 | issue = 9 | pages = 555–61 | year = 1988 | pmid = 3407357 }}</ref>  EPF has also been proposed as a marker of viable pregnancy, more useful in distinguishing ectopic or other nonviable pregnancies than other chemical markers such as hCG and [[progesterone]].<ref>{{cite journal | vauthors = Straube W, Loh M, Leipe S | title = [Significance of the detection of early pregnancy factor for monitoring normal and disordered early pregnancy] | journal = Geburtshilfe und Frauenheilkunde | volume = 48 | issue = 12 | pages = 854–8 | date = Dec 1988 | pmid = 2466731 | doi = 10.1055/s-2008-1026640 | s2cid = 260158786 }}</ref><ref>{{cite journal | vauthors = Gerhard I, Katzer E, Runnebaum B | title = The early pregnancy factor (EPF) in pregnancies of women with habitual abortions | journal = Early Human Development | volume = 26 | issue = 2 | pages = 83–92 | year = 1991 | pmid = 1720719 | doi = 10.1016/0378-3782(91)90012-R }}</ref><ref>{{cite journal | vauthors = Shu-Xin H, Zhen-Qun Z | title = A study of early pregnancy factor activity in the sera of patients with unexplained spontaneous abortion | journal = American Journal of Reproductive Immunology | volume = 29 | issue = 2 | pages = 77–81 | date = Mar 1993 | pmid = 8329108 | doi = 10.1111/j.1600-0897.1993.tb00569.x | s2cid = 22163702 }}</ref><ref>{{cite journal | vauthors = Shahani SK, Moniz CL, Bordekar AD, Gupta SM, Naik K | title = Early pregnancy factor as a marker for assessing embryonic viability in threatened and missed abortions | journal = Gynecologic and Obstetric Investigation | volume = 37 | issue = 2 | pages = 73–6 | year = 1994 | pmid = 8150373 | doi = 10.1159/000292528 }}</ref>

=== As a tumour marker ===

Although almost exclusively associated with pregnancy, EPF-like activity has also been detected in tumors of germ cell origin<ref>{{cite journal | vauthors = Rolfe BE, Morton H, Cavanagh AC, Gardiner RA | title = Detection of an early pregnancy factor-like substance in sera of patients with testicular germ cell tumors | journal = American Journal of Reproductive Immunology | volume = 3 | issue = 2 | pages = 97–100 | date = Mar 1983 | pmid = 6859385 | doi = 10.1111/j.1600-0897.1983.tb00223.x | s2cid = 33423830 }}</ref><ref>{{cite journal | vauthors = Mehta AR, Shahani SK | title = Detection of early pregnancy factor-like activity in women with gestational trophoblastic tumors | journal = American Journal of Reproductive Immunology and Microbiology | volume = 14 | issue = 3 | pages = 67–9 | date = Jul 1987 | pmid = 2823620 | doi=10.1111/j.1600-0897.1987.tb00122.x}}</ref> and in other types of tumors.<ref>{{cite journal | vauthors = Quinn KA, Athanasas-Platsis S, Wong TY, Rolfe BE, Cavanagh AC, Morton H | title = Monoclonal antibodies to early pregnancy factor perturb tumour cell growth | journal = Clinical and Experimental Immunology | volume = 80 | issue = 1 | pages = 100–8 | date = Apr 1990 | pmid = 2323098 | pmc = 1535227 | doi = 10.1111/j.1365-2249.1990.tb06448.x }}</ref>  Its utility as a tumour marker, to evaluate the success of surgical treatment, has been suggested.<ref>{{cite journal | vauthors = Bojahr B, Straube W, Reddemann H | title = [Case observations on the significance of early pregnancy factor as a tumor marker] | journal = Zentralblatt für Gynäkologie | volume = 115 | issue = 3 | pages = 125–8 | year = 1993 | pmid = 7682025 }}</ref>

== References ==
{{reflist|33em}}

== Further reading ==
{{refbegin|33em}}
* {{cite journal | vauthors = Czarnecka AM, Campanella C, Zummo G, Cappello F | title = Heat shock protein 10 and signal transduction: a "capsula eburnea" of carcinogenesis? | journal = Cell Stress & Chaperones | volume = 11 | issue = 4 | pages = 287–94 | year = 2006 | pmid = 17278877 | pmc = 1713189 | doi = 10.1379/CSC-200.1 | doi-broken-date = 12 July 2025 }}
* {{cite journal | vauthors = Legname G, Fossati G, Gromo G, Monzini N, Marcucci F, Modena D | title = Expression in Escherichia coli, purification and functional activity of recombinant human chaperonin 10 | journal = FEBS Lett. | volume = 361 | issue = 2–3 | pages = 211–4 | year = 1995 | pmid = 7698325 | doi = 10.1016/0014-5793(95)00184-B | s2cid = 22185852 | doi-access = free | bibcode = 1995FEBSL.361..211L }}
* {{cite journal | vauthors = Cavanagh AC, Morton H | title = The purification of early-pregnancy factor to homogeneity from human platelets and identification as chaperonin 10 | journal = Eur. J. Biochem. | volume = 222 | issue = 2 | pages = 551–60 | year = 1994 | pmid = 7912672 | doi = 10.1111/j.1432-1033.1994.tb18897.x | doi-access = free }}
* {{cite journal | vauthors = Monzini N, Legname G, Marcucci F, Gromo G, Modena D | title = Identification and cloning of human chaperonin 10 homologue | journal = Biochim. Biophys. Acta | volume = 1218 | issue = 3 | pages = 478–80 | year = 1994 | pmid = 7914093 | doi = 10.1016/0167-4781(94)90211-9 }}
* {{cite journal | vauthors = Chen JJ, McNealy DJ, Dalal S, Androphy EJ | title = Isolation, sequence analysis and characterization of a cDNA encoding human chaperonin 10 | journal = Biochim. Biophys. Acta | volume = 1219 | issue = 1 | pages = 189–90 | year = 1994 | pmid = 7916212 | doi = 10.1016/0167-4781(94)90268-2 }}
* {{cite journal | vauthors = Samali A, Cai J, Zhivotovsky B, Jones DP, Orrenius S | title = Presence of a pre-apoptotic complex of pro-caspase-3, Hsp60 and Hsp10 in the mitochondrial fraction of jurkat cells | journal = EMBO J. | volume = 18 | issue = 8 | pages = 2040–8 | year = 1999 | pmid = 10205158 | pmc = 1171288 | doi = 10.1093/emboj/18.8.2040 }}
* {{cite journal | vauthors = Summers KM, Fletcher BH, Macaranas DD, Somodevilla-Torres MJ, Murphy RM, Osborne MJ, Spurr NK, Cassady AI, Cavanagh AC | title = Mapping and characterization of the eukaryotic early pregnancy factor/chaperonin 10 gene family | journal = Somat. Cell Mol. Genet. | volume = 24 | issue = 6 | pages = 315–26 | year = 1998 | pmid = 10763410 | doi = 10.1023/A:1024488422990 | s2cid = 39860709 }}
* {{cite journal | vauthors = Richardson A, Schwager F, Landry SJ, Georgopoulos C | title = The importance of a mobile loop in regulating chaperonin/ co-chaperonin interaction: humans versus Escherichia coli | journal = J. Biol. Chem. | volume = 276 | issue = 7 | pages = 4981–7 | year = 2001 | pmid = 11050098 | doi = 10.1074/jbc.M008628200 | doi-access = free }}
* {{cite journal | vauthors = Fletcher BH, Cassady AI, Summers KM, Cavanagh AC | title = The murine chaperonin 10 gene family contains an intronless, putative gene for early pregnancy factor, Cpn10-rs1 | journal = Mamm. Genome | volume = 12 | issue = 2 | pages = 133–40 | year = 2001 | pmid = 11210183 | doi = 10.1007/s003350010250 | s2cid = 21105180 }}
* {{cite journal | vauthors = Parissi V, Calmels C, De Soultrait VR, Caumont A, Fournier M, Chaignepain S, Litvak S | title = Functional interactions of human immunodeficiency virus type 1 integrase with human and yeast HSP60 | journal = J. Virol. | volume = 75 | issue = 23 | pages = 11344–53 | year = 2001 | pmid = 11689615 | pmc = 114720 | doi = 10.1128/JVI.75.23.11344-11353.2001 }}
* {{cite journal | vauthors = Hansen JJ, Dürr A, Cournu-Rebeix I, Georgopoulos C, Ang D, Nielsen MN, Davoine CS, Brice A, Fontaine B, Gregersen N, Bross P | title = Hereditary spastic paraplegia SPG13 is associated with a mutation in the gene encoding the mitochondrial chaperonin Hsp60 | journal = Am. J. Hum. Genet. | volume = 70 | issue = 5 | pages = 1328–32 | year = 2002 | pmid = 11898127 | pmc = 447607 | doi = 10.1086/339935 }}
* {{cite journal | vauthors = Guidry JJ, Wittung-Stafshede P | title = Low stability for monomeric human chaperonin protein 10: interprotein interactions contribute majority of oligomer stability | journal = Arch. Biochem. Biophys. | volume = 405 | issue = 2 | pages = 280–2 | year = 2002 | pmid = 12220543 | doi = 10.1016/S0003-9861(02)00406-X }}
* {{cite journal | vauthors = Lee KH, Kim HS, Jeong HS, Lee YS | title = Chaperonin GroESL mediates the protein folding of human liver mitochondrial aldehyde dehydrogenase in Escherichia coli | journal = Biochem. Biophys. Res. Commun. | volume = 298 | issue = 2 | pages = 216–24 | year = 2002 | pmid = 12387818 | doi = 10.1016/S0006-291X(02)02423-3 }}
* {{cite journal | vauthors = Hansen JJ, Bross P, Westergaard M, Nielsen MN, Eiberg H, Børglum AD, Mogensen J, Kristiansen K, Bolund L, Gregersen N | title = Genomic structure of the human mitochondrial chaperonin genes: HSP60 and HSP10 are localised head to head on chromosome 2 separated by a bidirectional promoter | journal = Hum. Genet. | volume = 112 | issue = 1 | pages = 71–7 | year = 2003 | pmid = 12483302 | doi = 10.1007/s00439-002-0837-9 | s2cid = 25856774 }}
* {{cite journal | vauthors = Mansell JP, Yarram SJ, Brown NL, Sandy JR | title = Type I collagen synthesis by human osteoblasts in response to placental lactogen and chaperonin 10, a homolog of early-pregnancy factor | journal = In Vitro Cell. Dev. Biol. Anim. | volume = 38 | issue = 9 | pages = 518–22 | year = 2002 | pmid = 12703979 | doi = 10.1290/1071-2690(2002)038<0518:TICSBH>2.0.CO;2 | s2cid = 24606162 }}
* {{cite journal | vauthors = Cappello F, Bellafiore M, David S, Anzalone R, Zummo G | title = Ten kilodalton heat shock protein (HSP10) is overexpressed during carcinogenesis of large bowel and uterine exocervix | journal = Cancer Lett. | volume = 196 | issue = 1 | pages = 35–41 | year = 2003 | pmid = 12860287 | doi = 10.1016/S0304-3835(03)00212-X | hdl = 10447/191095 | url = https://iris.unipa.it/bitstream/10447/191095/1/OP%2012.%20Cappello%20et%20al%252c%20Cancer%20Lett%202003.pdf | hdl-access = free }}
* {{cite journal | vauthors = Shan YX, Liu TJ, Su HF, Samsamshariat A, Mestril R, Wang PH | title = Hsp10 and Hsp60 modulate Bcl-2 family and mitochondria apoptosis signaling induced by doxorubicin in cardiac muscle cells | journal = J. Mol. Cell. Cardiol. | volume = 35 | issue = 9 | pages = 1135–43 | year = 2003 | pmid = 12967636 | doi = 10.1016/S0022-2828(03)00229-3 }}
* {{cite journal | vauthors = Shan YX, Yang TL, Mestril R, Wang PH | title = Hsp10 and Hsp60 suppress ubiquitination of insulin-like growth factor-1 receptor and augment insulin-like growth factor-1 receptor signaling in cardiac muscle: implications on decreased myocardial protection in diabetic cardiomyopathy | journal = J. Biol. Chem. | volume = 278 | issue = 46 | pages = 45492–8 | year = 2003 | pmid = 12970367 | doi = 10.1074/jbc.M304498200 | doi-access = free }}
* {{cite journal | vauthors = Guidry JJ, Shewmaker F, Maskos K, Landry S, Wittung-Stafshede P | title = Probing the interface in a human co-chaperonin heptamer: residues disrupting oligomeric unfolded state identified | journal = BMC Biochem. | volume = 4 | article-number = 14 | year = 2003 | pmid = 14525625 | pmc = 270013 | doi = 10.1186/1471-2091-4-14 | doi-access = free }}
{{refend}}

== External links ==
* {{MeshName|GroES+Protein}}
*[https://www.pdbe.org/emsearch/groes 3D macromolecular structures of GroES in EMDB]

{{Chaperones}}
{{InterPro content|IPR020818}}

[[Category:Protein domains]]
[[Category:Protein complexes]]
[[Category:Tests for pregnancy]]
[[Category:Moonlighting proteins]]
[[Category:Co-chaperones]]