Part of the ESX-3 specialized secretion system, which is important for iron and zinc uptake or homeostasis. Part of the ESX-3 / type VII secretion system (T7SS), which is composed of cytosolic and membrane components. The ESX-3 membrane complex is composed of EccB3, EccC3, EccD3 and EccE3. Repressed by IdeR in the presence of iron and by Zur in the presence of zinc. Belongs to the EccE family.