ErbB-3 and ErbB-4 function as the respective low and high affinity receptors of all Neu differentiation factor/heregulin isoforms.

摘要: Neu differentiation factor (NDF or heregulin) elevates tyrosine phosphorylation of the ErbB-2 receptor kinase, and it was, therefore, thought to function as a ligand this receptor. However, several lines evidence raised possibility that interaction between NDF involves another molecule, which belongs family epidermal growth receptors. To address question we constructed soluble chimeric proteins alkaline phosphatase extracellular domains either ErbB-3 ErbB-4, two newly recognized members family. Using found beta isoforms specifically bind ErbB-4 receptors but not protein. When ectopically expressed in monkey fibroblasts, full-length conferred specific binding NDF. In these cells displayed lower affinity than like latter preferred isoform over alpha class NDFs. These results indicate both physiological all suggest still unknown exists.