Dataset Information

Structural Elements in the Transmembrane and Cytoplasmic Domains of the Metal Transporter SLC30A10 Are Required for Its Manganese Efflux Activity.

ABSTRACT: Homozygous mutations in SLC30A10 lead to the development of familial manganese-induced parkinsonism. We previously demonstrated that SLC30A10 is a cell surface-localized manganese efflux transporter, and parkinsonism-causing mutations block its trafficking and efflux activity. Interestingly, other transporters in the SLC30 family mediate zinc efflux. Determining the mechanisms that allow SLC30A10 to transport manganese, which are unclear, is essential to understand its role in parkinsonism. Here, we generated a predicted structure of SLC30A10, based on the structure of the bacterial zinc transporter YiiP, and performed functional studies. In YiiP, side chains of residues Asp-45 and Asp-49 in the second and His-153 and Asp-157 in the fifth transmembrane segments coordinate zinc and are required for transport. In SLC30A10, the corresponding residues are Asn-43 and Asp-47 in the second and His-244 and Asp-248 in the fifth transmembrane segments. Surprisingly, although alanine substitution of Asp-248 abolished manganese efflux, that of Asn-43 and Asp-47 did not. Instead, side chains of charged or polar residues adjacent to Asp-248 in the first (Glu-25) or fourth (Asn-127) transmembrane segments were required. Further analyses revealed that residues His-333 and His-350 in the cytoplasmic C-terminal domain were required for full activity. However, the C-terminal domain failed to transfer manganese transport capability to a related zinc transporter. Overall, our results indicate that residues in the transmembrane and C-terminal domains together confer optimal manganese transport capability to SLC30A10 and suggest that the mechanism of ion coordination in the transmembrane domain of SLC30A10 may be substantially different from that in YiiP/other SLC30 proteins.

SUBMITTER: Zogzas CE

PROVIDER: S-EPMC4965547 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Structural Elements in the Transmembrane and Cytoplasmic Domains of the Metal Transporter SLC30A10 Are Required for Its Manganese Efflux Activity.

Zogzas Charles E CE Aschner Michael M Mukhopadhyay Somshuvra S

The Journal of biological chemistry 20160615 31

Homozygous mutations in SLC30A10 lead to the development of familial manganese-induced parkinsonism. We previously demonstrated that SLC30A10 is a cell surface-localized manganese efflux transporter, and parkinsonism-causing mutations block its trafficking and efflux activity. Interestingly, other transporters in the SLC30 family mediate zinc efflux. Determining the mechanisms that allow SLC30A10 to transport manganese, which are unclear, is essential to understand its role in parkinsonism. Here ...[more]

PMID: 27307044

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Project description:The activity of the manganese (Mn) efflux transporter SLC30A10 in the liver and intestines is critical for Mn excretion and preventing Mn toxicity. Homozygous loss-of-function mutations in SLC30A10 are a well-established cause of hereditary Mn toxicity. But, the relationship between more common SLC30A10 polymorphisms, Mn homeostasis, and disease is only recently emerging. In 2021, the first coding SNP in SLC30A10 (T95I) was associated with liver disease raising the hypothesis that the T95I substitution may induce disease by inhibiting the Mn efflux function of SLC30A10. Here, we test this hypothesis using structural, viability, and metal quantification approaches. Analyses of a predicted structure of SLC30A10 revealed that the side chain of T95 pointed away from the putative Mn-binding cavity, raising doubts about the impact of the T95I substitution on SLC30A10 function. In HeLa or HepG2 cells, overexpression of SLC30A10-WT or T95I resulted in comparable reductions of intracellular Mn levels and protection against Mn-induced cell death. Furthermore, ΔSLC30A10 HepG2 cells, generated using CRISPR/Cas9, exhibited elevated Mn levels and heightened sensitivity to Mn-induced cell death, and these phenotypic changes were similarly rescued by expression of SLC30A10-WT or T95I. Finally, turnover rates of SLC30A10-WT or T95I were also comparable. In summary, our results indicate that the Mn transport activity of SLC30A10-T95I is essentially comparable to the WT protein. Our findings imply that SLC30A10-T95I either has a complex association with liver injury that extends beyond the simple reduction in SLC30A10 activity or alternatively the T95I mutation lacks a causal role in liver disease.NEW & NOTEWORTHY This study demonstrates that the T95I polymorphism in the manganese transporter SLC30A10, which has been associated with liver disease in human GWAS studies, does not impact transporter function in cell culture. These findings raise doubts about the causal relationship of the T95I polymorphism with human disease and highlight the importance of validating GWAS findings using mechanistic approaches.

Dataset Information

Structural Elements in the Transmembrane and Cytoplasmic Domains of the Metal Transporter SLC30A10 Are Required for Its Manganese Efflux Activity.

Publications

Structural Elements in the Transmembrane and Cytoplasmic Domains of the Metal Transporter SLC30A10 Are Required for Its Manganese Efflux Activity.

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