Activin Receptors, Type IIActivin ReceptorsActivinsActivin Receptors, Type IMyostatinInhibinsInhibin-beta SubunitsFollistatinReceptors, Growth FactorLigandsSodium-Phosphate Cotransporter Proteins, Type IIaSmad2 ProteinReceptors, Transforming Growth Factor betaGroup II Phospholipases A2Signal TransductionTransforming Growth Factor betaSodium-Phosphate Cotransporter ProteinsBone Morphogenetic ProteinsRNA, MessengerNodal ProteinSmad ProteinsMolecular Sequence DataGrowth Differentiation FactorsBone Morphogenetic Protein Receptors, Type IAmino Acid SequenceGene ExpressionBone Morphogenetic Protein Receptors, Type IIMesodermProtein-Serine-Threonine KinasesIn Situ HybridizationSmad3 ProteinSmad4 ProteinProtein BindingCell LineCells, CulturedGrowth SubstancesGene Expression Regulation, DevelopmentalMuscle Fibers, Fast-TwitchEmbryonic InductionGlycoproteinsCell DifferentiationXenopus ProteinsBase SequenceMuscle Fibers, Slow-TwitchNonmuscle Myosin Type IIAReverse Transcriptase Polymerase Chain ReactionXenopusTrans-ActivatorsMyositis OssificansImmunohistochemistryMice, Inbred C57BLGranulosa CellsReceptors, Cell SurfaceMuscle, SkeletalMyosin Heavy Chains