In certain aspects, the disclosure provides soluble heteromeric polypeptide complexes comprising an extracellular domain of a type I serine/threonine kinase receptor of the TGF-beta family and an extracellular domain of a type II serine/threonine kinase receptor of the TGF-beta family. In some embodiments, the disclosure provides soluble polypeptide complexes comprising an extracellular domain of a type II receptor selected from: ActRIIA, ActRIIB, TGFBRII, BMPRII, and MISRII. In some embodiments, the disclosure provides soluble polypeptide complexes comprising an extracellular domain of a type I receptor selected from: ALK1, ALK2, ALK3, ALK4, ALK5, ALK6, and ALK7. Optionally the soluble complex is a heterodimer. In certain aspects, such soluble polypeptide complexes may be used to regulate (promote or inhibit) growth of tissues or cells including, for example, muscle, bone, cartilage, fat, neural tissue, tumors, cancerous cells, and/or cells of hematopoietic lineages, including red blood cells. In certain aspects, such soluble polypeptide complexes are can be used to improve muscle formation, bone formation, hematopoiesis, metabolic parameters, and disorders associated with these tissues, cellular networks, and endocrine systems.Selon certains aspects, la présente invention concerne des complexes polypeptidiques hétéromères solubles comprenant un domaine extracellulaire d'un récepteur ALK7 et un domaine extracellulaire de ActRIIB. Selon certains aspects, ces hétéromultimères ALK7:ActRIIB sont/peuvent être utilisés pour améliorer des paramètres métaboliques chez un patient qui en a besoin. Selon certains aspects, ces hétéromultimères ALK7:ActRIIB sont/peuvent être utilisés pour traiter ou prévenir une ou plusieurs maladies ou affections associées au rein chez un patient qui en a besoin.
