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Neuregulin 3
Encoded by human NRG3 Gene (NRG Family), conserved 720-aa Neuregulin 3 is a brain and testis soluble growth and differentiation factor, and a type I membrane protein containing 2 hydrophobic segments similar to the transmembrane domain and internal signal sequence in NRG1. NRG3 also contains an N-Ala/Gly-rich segment, an EGF motif, and a mucin-like Ser/Thr-rich region with sites for O-linked glycosylation. Membrane-bound NRG3 may be inactive. Preceded by extensive glycosylation, external proteolytic cleavage close to the plasma membrane may involve dimerization of the intracellular domain. A ligand for ERBB4 receptor tyrosine kinase (likely via the EGF-like domain), NRG3 does not bind to ERBB2, ERBB3, or EGF receptor. The ERBB4 binding sites of NRG1 and NRG3 may overlap. (from LocusLink, Swiss-Prot, OMIM, and NCI) (NCI Thesaurus)