The function of SLC39A9 (solute carrier family 39 member 9, ENSG00000029364) is as follows. Transports zinc ions across cell and organelle membranes into the cytoplasm and regulates intracellular zinc homeostasis (PubMed:19420709, PubMed:25014355, PubMed:28219737). Participates in the zinc ions efflux out of the secretory compartments (PubMed:19420709). Regulates intracellular zinc level, resulting in the enhancement of AKT1 and MAPK3/MAPK1 (Erk1/2) phosphorylation in response to the BCR activation (PubMed:23505453). Also functions as a membrane androgen receptor that mediates, through a G protein, the non- classical androgen signaling pathway, characterized by the activation of MAPK3/MAPK1 (Erk1/2) and transcription factors CREB1 or ATF1 (By similarity). This pathway contributes to CLDN1 and CLDN5 expression and tight junction formation between adjacent Sertoli cells (By similarity). Mediates androgen-induced vascular endothelial cell proliferation through activation of an inhibitory G protein leading to the AKT1 and MAPK3/MAPK1 (Erk1/2) activation which in turn modulate inhibition (phosphorylation) of GSK3B and CCND1 transcription (PubMed:34555425). Moreover, has dual functions as a membrane-bound androgen receptor and as an androgen-dependent zinc transporter both of which are mediated through an inhibitory G protein (Gi) that mediates both MAP kinase and zinc signaling leading to the androgen-dependent apoptotic process (PubMed:25014355, PubMed:28219737). {ECO:0000250|UniProtKB:Q3KR82, ECO:0000250|UniProtKB:Q8BFU1, ECO:0000269|PubMed:19420709, ECO:0000269|PubMed:23505453, ECO:0000269|PubMed:25014355, ECO:0000269|PubMed:28219737, ECO:0000269|PubMed:34555425}.