Theestrogen-inducIBLeRINGfingerproteinEfpstimulatesproliferationofbreastcancercells.14-3-3isp53-inducibleproteinthatsequestersmitoticCdksinthecytoplasmtoinhibitentryintomitosis.Toallowcell-cycleprogression,estrogensstimulateproductionofEfp,whichbindsandubiquinates14-3-3ssigma.14-3-3smarkedwithubiquitinchainsisrecognizedanddestroyedbytheproteosome.ReleasedCdksarenowfreetoescapeintothenucleusandpromotemitoticentry. Contributor:KosiGramatikoff,PhD REFERENCES:AkiraOrimo,SatoshiInoue,KazuhiroIkeda,SumihareNoji,andMasamiMuramatsuMolecularCloning,Structure,andExpressionofMouseEstrogen-responsiveFingerProteinEfpJ.Biol.Chem.,Oct1995;270:24406-24413.KIkeda,AOrimo,YHigashi,MMuramatsu,andSInoueEfpasaprimaryestrogen-responsivegeneinhumanbreastcancer.FEBSLett,Apr2000;472(1):9-13.TUrano,TSaito,TTsukui,MFujita,THosoi,MMuramatsu,YOuchi,andSInoueEfptargets14-3-3sigmaforproteolysisandpromotesbreasttumourgrowth.Nature,Jun2002;417(6891):871-5.