 However, it has been shown that TGF beta binds with high affinity to only a small amount of the available endoglin, which suggests that there is another factor regulating this binding.Endoglin itself doesn't bind the TGF beta ligands, but is present with the TGF beta receptors when the ligand is bound, indicating an important role for endoglin.The full length endoglin will bind to the TGF beta receptor complex whether TGF beta is bound or not, but the truncated forms of endoglin have more specific binding.