Mitochondrial proton-coupled zinc ion antiporter mediating the export of zinc from the mitochondria and involved in zinc homeostasis, zinc mobilization as well as mitochondrial morphology and health (PubMed:28334855, PubMed:34397090, PubMed:34433664, PubMed:35614220). In nucleus, functions as a secondary coactivator for nuclear receptors by cooperating with p160 coactivators subtypes. Plays a role in transcriptional activation of Wnt-responsive genes (By similarity).