Tyrosine-protein kinase that plays an essential role as cell surface receptor for neuregulins. Binds to neuregulin-1 (NRG1) and is activated by it; ligand-binding increases phosphorylation on tyrosine residues and promotes its association with the p85 subunit of phosphatidylinositol 3-kinase (PubMed:20682778). May also be activated by CSPG5 (PubMed:15358134). Involved in the regulation of myeloid cell differentiation (PubMed:27416908). {ECO:0000269|PubMed:15358134, ECO:0000269|PubMed:20682778, ECO:0000269|PubMed:27416908}. This is the function of ENSG00000065361 (ERBB3, erb-b2 receptor tyrosine kinase 3).