The TGF-13 superfamily is a large and expanding multigene family which in verte- brates includes the TGF-13 proteins themselves, the bone morphogenetic proteins (BMPs), the growth and differentiation factors (GDF), the activins/inhibins (INH), Mullerian inhibitory substance (MIS), glial derived neurotropic factor (GDNF) and more recently macrophage inhibitory cytokine 1 (MIC-1). They are characterised by conserved structural elements and a broad commonality of function. Major structural elements All members of the TGF-13 superfamily contain as their major structural hallmark a conserved...