Slc30a9, also known as ZnT9, is a mitochondria-resident zinc transporter. It plays a crucial role in maintaining mitochondrial zinc homeostasis, which is essential for multiple biological processes. It may be implicated in Wnt signaling and nuclear regulation, as well as in cell and mitochondrial zinc regulation [2,3].

In Drosophila melanogaster, knockdown of ZnT9 (ZnT49B) leads to impaired movement and mitochondrial deformation, with severe reduction or null mutants being pupal lethal [1]. In mice, germline loss of Znt9 causes mid-gestational lethality with severe development abnormalities, and targeted mutagenesis in the brain results in dwarfism, incapacitation, and death, along with almost non-existent GH/IGF-1 signals [1]. In humans, mutations in SLC30A9 are associated with a novel cerebro-renal syndrome, characterized by neurological deterioration, intellectual disability, ataxia, and oculomotor apraxia, with some patients also having early-onset nephropathy [2,5,6]. A mutation in the nematode Caenorhabditis elegans homologue of SLC30A9 increases sensitivity to oxidative stress, and knockdown of human SLC30A9 also causes increased ROS production in human cells [4].

In conclusion, Slc30a9 is essential for mitochondrial zinc homeostasis, and its dysfunction leads to severe consequences in development and disease. The study of Slc30a9 through gene knockout models in flies, nematodes, and mice has revealed its critical role in mammalian early embryonic development and in a novel cerebro-renal syndrome in humans. These findings contribute to our understanding of the biological functions of Slc30a9 and its implications in disease mechanisms [1,2,4].

References:

1. Ge, Jing, Li, Huihui, Liang, Xin, Zhou, Bing. 2024. SLC30A9: an evolutionarily conserved mitochondrial zinc transporter essential for mammalian early embryonic development. In Cellular and molecular life sciences : CMLS, 81, 357. doi:10.1007/s00018-024-05377-y. https://pubmed.ncbi.nlm.nih.gov/39158587/

2. Perez, Yonatan, Shorer, Zamir, Liani-Leibson, Keren, Landau, Daniel, Birk, Ohad S. . SLC30A9 mutation affecting intracellular zinc homeostasis causes a novel cerebro-renal syndrome. In Brain : a journal of neurology, 140, 928-939. doi:10.1093/brain/awx013. https://pubmed.ncbi.nlm.nih.gov/28334855/

3. Kleyner, Robert, Arif, Mohammad, Marchi, Elaine, Velinov, Milen, Lyon, Gholson J. 2022. Autosomal recessive SLC30A9 variants in a proband with a cerebrorenal syndrome and no parental consanguinity. In Cold Spring Harbor molecular case studies, 8, . doi:10.1101/mcs.a006137. https://pubmed.ncbi.nlm.nih.gov/34716203/

4. En, Atsuki, Takanashi, Shuo, Okazaki, Rena, Fujii, Michihiko. 2022. A mutation in SLC30A9, a zinc transporter, causes an increased sensitivity to oxidative stress in the nematode Caenorhabditis elegans. In Biochemical and biophysical research communications, 634, 175-181. doi:10.1016/j.bbrc.2022.09.107. https://pubmed.ncbi.nlm.nih.gov/36244116/

5. Steel, Dora Batia Dyne, Danti, Federica Rachele, Abunada, Mohamed, Barwick, Katy, Kurian, Manju A. 2023. Clinical Phenotype in Individuals With Birk-Landau-Perez Syndrome Associated With Biallelic SLC30A9 Pathogenic Variants. In Neurology, 100, e2214-e2223. doi:10.1212/WNL.0000000000207241. https://pubmed.ncbi.nlm.nih.gov/37041080/

6. Kizhakkedath, Praseetha, AlDhaheri, Watfa, Baydoun, Ibrahim, Al-Jasmi, Fatma, Alblooshi, Hiba. 2023. Case report: Birk-Landau-Perez syndrome linked to the SLC30A9 gene-identification of additional cases and expansion of the phenotypic spectrum. In Frontiers in genetics, 14, 1219514. doi:10.3389/fgene.2023.1219514. https://pubmed.ncbi.nlm.nih.gov/37576556/