ErbB
![Comparison of ErbB extracellular domain structures](/Images/godic/202501/11/Erb_fig3811.jpeg")
![A superposition of similar interfaces observed in crystal structures of the ERBB kinases, including EGFR, ERBB2 (HER2) and ERBB4 (HER4). The protein chains are colored from blue to red from N to C terminus. The kinase at the top of each dimer (as shown) activates the kinase at the bottom of each dimer (Zhang et al., Cell v. 125, pp. 1137-1149, 2008). The cluster was identified with the ProtCID database. The image was made with PyMOL.](/Images/godic/202501/11/Activation_of_ERBB_kinases3811.png")
The ErbB family of proteins contains four receptor tyrosine kinases, structurally related to the epidermal growth factor receptor (EGFR), its first discovered member. In humans, the family includes Her1 (EGFR, ErbB1), Her2 (Neu, ErbB2), Her3 (ErbB3), and Her4 (ErbB4). The gene symbol, ErbB, is derived from the name of a viral oncogene to which these receptors are homologous: erythroblastic leukemia viral oncogene. Insufficient ErbB signaling in humans is associated with the development of neurodegenerative diseases, such as multiple sclerosis and Alzheimer's Disease, while excessive ErbB signaling is associated with the development of a wide variety of types of solid tumor.