Type:Protein
SpeciesReactivity:H
B=Bovine;Ca=Cat;Ch=Chicken;D=Dog;EQ=Equine;GP=GuineaPig;H=Human;M=Mouse;P=Porcine;Pr=Primate;R=Rat;Rb=Rabbit;Y=Yeast;Xe=Xenopus;Ze=Zebrafish;;;;NA-NotApplicable;STP=Step-TactinProteins;AllActivins,membersoftheTGF-betasuperfamily,aredisulfide-linkeddimericproteinsoriginallypurifiedfromgonadalfluidsasproteinsthatstimulatedpituitaryfolliclestimulatinghormone(FSH)release.ActivinproteinshaveawiderangeofBIOLOGicalactivities,includingmesoderminduction,neuralcelldifferentiation,boneremodeling,hematopoiesisandrolesinreproductivephysiology.ActivinisoformsandothermembersoftheTGF-betasuperfamilyexerttheirbiologicaleffectsbybindingtoheteromericcomplexesofatypeIandatypeIIserine-threoninekinasereceptor,bothofwhichareessentialforsignaltransduction.
Activinsarehomodimersorheterodimersofthevariousbetasubunitisoforms,whileinhibinsareheterodimersofauniquealphasubunitandoneofthevariousbetasubunits.Fivebetasubunits(mammalianbetaA,betaB,betaC,betaEandXenopusbetaD)havebeenclonedtodate.Theactivin/inhibinnomenclaturereflectsthesubunitcompositionoftheproteins:ActivinA(betaA-betaA),ActivinB(betaB-betaB),ActivinAB(betaA-betaB),InhibinA(alpha-betaA)andInhibinB(alpha-betaB).