SRC tyrosine kinase, activated by EGFR signaling, binds to the cleaved intracellular fragment of ERBB4, ERBB4s80 (E4ICD), released in response to ERBB4 activation by NRG1. Tyrosine phosphorylation of ERBB4s80 is needed for SRC binding. It is not clear whether tyrosine phosphorylation sites are auto-phosphorylated or phosphorylated by SRC. SRC binding prevents translocation of ERBB4s80 to the nucleus (Ishibashi et al. 2012).