8.A.206.  The Zip8 Regulator 1 (Zip8R1) Family 

C9orf85 and CXorf38 are two previously uncharacterized human proteins associated with ZIP8 malfunction (Tan et al. 2022). The former protein has 179 aas and possibly one C-terminal TMS.  Human metal cation symporter ZIP8 (SLC39A8) is a member of the solute carrier family responsible for intracellular transport of essential micronutrients, including manganese, selenium, and zinc. Previously, Tan et al. 2022 established a ZIP8-knockout (KO) human cell model and explored how the expression of ZIP8 could contribute to a range of human diseases. C9orf85 and CXorf38 were amongst the top-10 most downregulated proteins in a Zip8 knockout mutant, and their expressions could be selectively induced by essential micronutrients. Analyses indicated a positive correlation between the gene expressions of ZIP8 and C9orf85 or CXorf38. The differentially expressed proteins identified in ZIP8-KO cells could be potential targets for diagnosing and/or treating human ZIP8-associated diseases, including malnutrition, viral infection, and cancers (Tan et al. 2022). Amoung it's homologs is a large serine/threonine-protein phosphatase 6 regulatory ankyrin repeat subunit B-like protein and many others.



Tan, H.W., Y.M. Xu, Z.L. Liang, N.L. Cai, Y.Y. Wu, and A.T.Y. Lau. (2022). Single-gene knockout-coupled omics analysis identifies C9orf85 and CXorf38 as two uncharacterized human proteins associated with ZIP8 malfunction. Front Mol Biosci 9: 991308.


TC#NameOrganismal TypeExample

Uncharacteerized protein, human CXorf38, shown to influence the activity of the Zip8 heavy metal transporter (TC# 2.A.5.4.15). It has 319 aas and 1 N-terminal TMS. See the Zip8 Regulator 1 (Zip8R1) family description for details of this regulation (Tan et al. 2022).

CXorf38 of Homo sapiens


Uncharacterized protein of 354 aas and possibly two TMSs, one at about residue 65 and one at the C-terminus of the protein.

UP of Dreissena polymorpha


Uncharacterized protein of 378 aas and possibly 1 TMS at about residue 65.

UP of Mya arenaria


Polyamine-modulated factor 1-binding protein 1-like protein of 517 aas.

PM factor of Mercenaria mercenaria