Direct ligand for ERBB3 and ERBB4 tyrosine kinase receptors. Concomitantly recruits ERBB1 and ERBB2 coreceptors, resulting in ligand-stimulated tyrosine phosphorylation and activation of the ERBB receptors. The multiple isoforms perform diverse functions such as inducing growth and differentiation of epithelial, glial, neuronal, and skeletal muscle cells, inducing expression of acetylcholine receptor in synaptic vesicles during the formation of the neuromuscular junction, stimulating lobuloalveolar budding and milk production in the mammary gland and inducing differentiation of mammary tumor cells, stimulating Schwann cell proliferation, implication in the development of the myocardium such as trabeculation of the developing heart. Isoform 10 may play a role in motor and sensory neuron development.
