Involved in the development of several major noradrenergic neuron populations, including the locus coeruleus (PubMed:26056227). Involved in neuronal development and in neuromuscular junction formation. Binds Zn(2+) ion with high affinity (PubMed:40867536). The RNF220/ZC4H2 complex monoubiquitinates PHOX2A and PHOX2B to enhance their DNA-binding ability and transactivity (By similarity). {ECO:0000250|UniProtKB:Q68FG0, ECO:0000269|PubMed:23623388, ECO:0000269|PubMed:26056227, ECO:0000269|PubMed:40867536}. This is the function of ZC4H2 (zinc finger C4H2-type containing, ENSG00000126970).