Identification of a gain-of-function mutation in a Golgi P-type ATPase that enhances Mn
            <sup>2+</sup>
            efflux and protects against toxicity

Background: Yeast is a model system for the study of mechanisms governing eukaryotic Golgi-Mn 2ϩ homeostasis. Results: We provide evidence that calcium stimulates ER and late endosome/trans-to cis-Golgi manganese delivery and bypasses the need for Pmr1. Conclusion: Vesicle trafficking promotes organelle-specific ion interchange and cytoplasmic metal detoxification. Significance: Our findings open new perspectives on chemical modifiers of Hailey-Hailey disease.

Section: Discussionmentioning

confidence: 99%

Manganese Redistribution by Calcium-stimulated Vesicle Trafficking Bypasses the Need for P-type ATPase Function

García‐Rodríguez

Manzano-López

Muñoz-Bravo

et al. 2015

“…1D), indicating that SPCA1 functions by effluxing manganese to the extracellular side via the secretory pathway, as described previously (16,17).…”

Section: Hspca1-gfp Was Localized To the Golgi Apparatus In Spca1mentioning

confidence: 99%

“…This is particularly urgent because these transporters/channel proteins may play a role in an established clinical condition caused by excessive manganese accumulation (3,8,14). Of the proteins postulated to be involved in manganese detoxification/efflux, the Golgi-localized secretory pathway Ca 2ϩ -ATPase 1 (SPCA1), which is an ortholog of S. cerevisiae Pmr1p, is comparatively well charac-terized (15)(16)(17). Moreover, ATP13A2/PARK9 (hereafter ATP13A2) is involved in manganese detoxification (18) based on the observation that the S. cerevisiae ortholog Ypk9p protects cells from toxicity of manganese and other metals by vacuolar sequestration (19,20).…”

mentioning

confidence: 99%

“…This system is useful to explore metal homeostasis and membrane transport protein functions in vertebrate cells because DT40 cells have a similar homeostatic regulation system of metals to that of mammalian cells and allow efficient gene disruption because of their high homologous recombination activity (31). In this study, we investigated transporter/channel proteins that function in detoxification/efflux of manganese using DT40 cells deficient in the SPCA1 gene (SPCA1 Ϫ/Ϫ/Ϫ cells) because SPCA1 is involved in manganese resistance via its redelivery into the Golgi apparatus (16,17). Using SPCA1 Ϫ/Ϫ/Ϫ cells, which showed extreme sensitivity to high manganese concentrations, we compared six human proteins that are involved in manganese detoxification/efflux.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Direct Comparison of Manganese Detoxification/Efflux Proteins and Molecular Characterization of ZnT10 Protein as a Manganese Transporter

Nishito

Tsuji

Fujishiro

et al. 2016

Manganese homeostasis involves coordinated regulation of specific proteins involved in manganese influx and efflux. However, the proteins that are involved in detoxification/efflux have not been completely resolved nor has the basis by which they select their metal substrate. Here, we compared six proteins, which were reported to be involved in manganese detoxification/efflux, by evaluating their ability to reduce manganese toxicity in chicken DT40 cells, finding that human ZnT10 (hZnT10) was the most significant contributor. A domain swapping and substitution analysis between hZnT10 and the zincspecific transporter hZnT1 showed that residue Asn 43 , which corresponds to the His residue constituting the potential intramembranous zinc coordination site in other ZnT transporters, is necessary to impart hZnT10's unique manganese mobilization activity; residues Cys 52 and Leu 242 in transmembrane domains II and V play a subtler role in controlling the metal specificity of hZnT10. Interestingly, the His 3 Asn reversion mutant in hZnT1 conferred manganese transport activity and loss of zinc transport activity. These results provide important information about manganese detoxification/efflux mechanisms in vertebrate cells as well as the molecular characterization of hZnT10 as a manganese transporter.

“…From a translational perspective, prior studies suggest that enhancing efflux may be a useful strategy to protect against the onset or control the progression of familial and non-familial manganese-induced parkinsonism (13,18). As SLC30A10 is a major manganese efflux transporter, it is a promising candidate for therapeutic intervention.…”

mentioning

confidence: 99%

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

Zogzas

Aschner

Mukhopadhyay

2016

Self Cite

105

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.