Negative regulator of EGFR signaling in skin morphogenesis. Acts as a negative regulator for several EGFR family members, including ERBB2, ERBB3 and ERBB4. Inhibits EGFR catalytic activity by interfering with its dimerization. Inhibits autophosphorylation of EGFR, ERBB2 and ERBB4. Important for normal keratinocyte proliferation and differentiation. Plays a role in modulating the response to steroid hormones in the uterus. Required for normal response to progesterone in the uterus and for fertility. Mediates epithelial estrogen responses in the uterus by regulating ESR1 levels and activation. Important for regulation of endometrium cell proliferation. Important for normal prenatal and perinatal lung development (By similarity). Interacts with EGFR and ERBB2. Associated with the plasma membrane of basal skin keratinocytes. Translocates into the nucleus of differentiating suprabasal keratinocytes (By similarity). By cAMP, glucocorticoids, phorbol esters and insulin. The EGFR-binding region prevents binding of a cyclin-like activator to the EGFR kinase domain, and thereby keeps EGFR in an inactive conformation. Also maintains EGFR in an inactive conformation by preventing formation of an asymmetric homodimer (By similarity). Belongs to the MIG6 family.