CYBDOMs consist of a dopamine β-monooxygenase N-terminal (DOMON) domain and a membrane-bound cytochrome b561 domain. Two recent studies (Chen et al., Ren et al.) demonstrate that, in addition to the previously shown ferric reduction, these proteins can mediate ascorbate regeneration and calcium transport, pointing to multiple functions in plants.
Maniero et al. (Fri,) studied this question.