[6] Mammalian cells have two major groups of zinc transporter proteins; the ones that export zinc from the cytoplasm to the extracellular space (efflux), which are called ZnT (SLC30 family), and ZIP (SLC39 family) proteins[9] whose functions are in the opposite direction (influx).

[15] A study in 2014 utilised the latest research technologies to clone and express a particular cDNA of the female Atlantic croaker ovaries, which encoded a protein showing the characteristics of the canonical isoform of ZIP9, as a novel membrane androgen receptor(mAR).

[5] Since mibolerone and metribolone bind to and activate the nuclear androgen receptor (AR) but not ZIP9, they could potentially be employed to differentiate between AR- and ZIP9-mediated responses of testosterone.

[18][19] As a result, any dysfunction of zinc transporter proteins can be harmful for the cells, and some of them are associated with different cancers, diabetes and inflammation.

[18] For instance, through activation of ZIP9, testosterone has been found to increase intracellular zinc levels in breast cancer, prostate cancer, and ovarian follicle cells and to induce apoptosis in these cells, an action which may be mediated partially or fully by increased zinc concentrations.

[5][20] Mutations in the SLC39A9 gene can occur due to genetic deletion of the q24.1-24.3 band of base pairs within the human chromosome 14.

Patient specific clinical issues included ectopic organs, undescended testes, also called cryptorchidism, and malrotation of the small intestine.

A study done in Seattle, USA, established the presence of the fusion protein product of the SLC39A9-PLEKHD1 gene to be present in 124 cases of schizophrenia and was closely related to the pathophysiology of disease.

[23][24] The fusion protein had features from both the parent genes and also possessed the ability to interact with cellular signalling pathways involving kinases such as Akt and Erk, leading to their increased phosphorylation within the brain and a consequent onset of schizophrenia.

[29] As a result, ZIP9, which is involved in importing zinc into the cells, is potentially a target for therapeutic studies in the future regarding diabetes type2.