"In mammalian cell systems , a link between ATP13A2 and Mn 2+ , Ca 2+ , Cd 2+ , Zn 2+ , or Ni 2+ homeostasis has been reported. A protective effect of ATP13A2 overexpression toward Ni 2+ and Mn 2+ in mammalian NLF cells was described (Covy et al., 2012), whereas the knockdown of ATP13A2 increases the sensitivity of SHSY5Y cells toward Zn 2+ , but strangely not Mn 2+ . This challenges the view that ATP13A2 would be a Mn 2+ transporter. "
[Show abstract][Hide abstract] ABSTRACT: Mutations in ATP13A2 lead to Kufor-Rakeb syndrome, a parkinsonism with dementia. ATP13A2 belongs to the P-type transport ATPases, a large family of primary active transporters that exert vital cellular functions. However, the cellular function and transported substrate of ATP13A2 remain unknown. To discuss the role of ATP13A2 in neurodegeneration, we first provide a short description of the architecture and transport mechanism of P-type transport ATPases. Then, we briefly highlight key P-type ATPases involved in neuronal disorders such as the copper transporters ATP7A (Menkes disease), ATP7B (Wilson disease), the Na(+)/K(+)-ATPases ATP1A2 (familial hemiplegic migraine) and ATP1A3 (rapid-onset dystonia parkinsonism). Finally, we review the recent literature of ATP13A2 and discuss ATP13A2's putative cellular function in the light of what is known concerning the functions of other, better-studied P-type ATPases. We critically review the available data concerning the role of ATP13A2 in heavy metal transport and propose a possible alternative hypothesis that ATP13A2 might be a flippase. As a flippase, ATP13A2 may transport an organic molecule, such as a lipid or a peptide, from one membrane leaflet to the other. A flippase might control local lipid dynamics during vesicle formation and membrane fusion events.
"The Scientific World Journal in divalent cations transportation, we cannot exclude that copper may be one of the metals carried by this protein. On the other hand, Ni(II) was also tested because it is implied in a number of pathologies, including allergies and cancer [9– 11], and causes noxious effects on different other processes  , but as a divalent cation, it may be too transported by the same ATPase, noting that recently Park9 protein was shown to exert protection properties against nickel toxicity  . "
[Show abstract][Hide abstract] ABSTRACT: P1D2E3K4H5E6L7 (PK9-H), a fragment of Ypk9, the yeast homologue of the human Park9 protein, was studied for its coordination abilities towards Ni(II) and Cu(II) ions through mono- and bi-dimensional NMR techniques. Both proteins are involved in the transportation of metal ions, including manganese and nickel, from the cytosol to the lysosomal lumen. Ypk9 showed manganese detoxification role, preventing a Mn-induced Parkinsonism (PD) besides mutations in Park9, linked to a juvenile form of the disease. Here, we tested PK9-H with Cu(II) and Ni(II) ions, the former because it is an essential element ubiquitous in the human body, so its trafficking should be strictly regulated and one cannot exclude that Ypk9 may play a role in it, and the latter because, besides being a toxic element for many organisms and involved in different pathologies and inflammation states, it seems that the protein confers protection against it. NMR experiments showed that both cations can bind PK9-H in an effective way, leading to complexes whose coordination mode depends on the pH of the solution. NMR data have been used to build a model for the structure of the major Cu(II) and Ni(II) complexes. Structural changes in the conformation of the peptide with organized side chain orientation promoted by nickel coordination were detected.
The Scientific World Journal 03/2014; 2014:656201. DOI:10.1155/2014/656201 · 1.73 Impact Factor
"Mutations identified in most KRS patients follow an autosomal recessive trait involving two mutant alleles (homozygotes or compound heterozygotes) that cause mRNA degradation, protein misfolding/truncation and degradation (2–5). ATP13A2 protein has been localized to several cellular acidic vesicles, including lysosomes and autophagosomes (2–10). It was therefore proposed that ATP13A2 functions in the autophagy-lysosomal pathway (ALP). "
[Show abstract][Hide abstract] ABSTRACT: Human ATP13A2 (PARK9), a lysosomal type 5 P-type ATPase, has been associated with autosomal recessive early-onset Parkinson's disease (PD). ATP13A2 encodes a protein that is highly expressed in neurons and is predicted to function as a cation pump, although the substrate specificity remains unclear. Accumulation of zinc and mitochondrial dysfunction are established aetiological factors that contribute to PD, however their underlying molecular mechanisms are largely unknown. Using patient-derived human olfactory neurosphere cultures, which harbour loss-of-function mutations in both alleles of ATP13A2, we identified a low intracellular free zinc ion concentration ([Zn(2+)]i), altered expression of zinc transporters and impaired sequestration of Zn(2+) into autophagy-lysosomal pathway associated vesicles, indicating zinc dyshomeostasis occurs in the setting of ATP13A2 deficiency. Pharmacological treatments that increased [Zn(2+)]i also induced the production of reactive oxygen species and aggravation of mitochondrial abnormalities that gave rise to mitochondrial depolarisation, fragmentation and cell death due to ATP depletion. The toxic effect of Zn(2+) was blocked by ATP13A2 overexpression, Zn(2+) chelation, antioxidant treatment and promotion of mitochondrial fusion. Taken together, these results indicate that human ATP13A2 deficiency results in zinc dyshomeostasis and mitochondrial dysfunction. Our data provide insights into the molecular mechanisms of zinc dyshomeostasis in PD and its contribution to mitochondrial dysfunction with ATP13A2 as a molecular link between two distinctive aetiological factors of PD.
Human Molecular Genetics 01/2014; 23(11). DOI:10.1093/hmg/ddt623 · 6.39 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.