2.A.4.8.3
Zn²⁺ transporter, TMEM163 or Znt11, of 289 aas and 6 TMSs.  It interacts with TrpML1 (TC# 1.A.5.3.1), but by itself, it can pump out Zn²⁺ (Sanchez et al. 2019).  It may be involved in the human lipid storage disorder, mucolipidosis type IV (MLIV), caused by Zn²⁺ overload (Cuajungco et al. 2014). TMEM163 is found in synaptic vesicles where it is called SV31 (Burré et al. 2007). It plays a role in Zn²⁺ uptake into lysosomes (Cuajungco and Kiselyov 2017). TMEM163 proteins catalyze Zn²⁺ efflux from cells and are critical for the biogenesis of platelet dense granules in mice (Yuan et al. 2021). TMEM163's discovery, transport feature, protein interactome, and similarities, as well as differences, with known SLC30 (ZnT) protein family members have been reviewed (Styrpejko and Cuajungco 2021). These authors also examined recent reports that implicate TMEM163 directly or indirectly in various human diseases such as Parkinson's disease, Mucolipidosis type IV and diabetes. TMEM163 is a dimer that catalyzes Zn²⁺ efflux from cells, or uptake into intracellular vesicles including lysosomes. TMEM163 dimerizes with itself, but it also heterodimerizes with ZNT1, ZNT2, ZNT3, and ZNT4 proteins (Escobar et al. 2022).