Protection against Mitochondrial and Metal Toxicity Depends on Functional Lipid Binding Sites in ATP13A2

Abstract

The late endo-/lysosomal P-type ATPase ATP13A2 (PARK9) is implicated in Parkinson's disease (PD) and Kufor-Rakeb syndrome, early-onset atypical Parkinsonism. ATP13A2 interacts at the N-terminus with the signaling lipids phosphatidic acid (PA) and phosphatidylinositol (3,5) bisphosphate (PI(3,5)P2), which modulate ATP13A2 activity under cellular stress conditions. Here, we analyzed stable human SHSY5Y cell lines overexpressing wild-type (WT) or ATP13A2 mutants in which three N-terminal lipid binding sites (LBS1–3) were mutated. We explored the regulatory role of LBS1–3 in the cellular protection by ATP13A2 against mitochondrial stress induced by rotenone and found that the LBS2-3 mutants displayed an abrogated protective effect. Moreover, in contrast to WT, the LBS2 and LBS3 mutants responded poorly to pharmacological inhibition of, respectively, PI(3,5)P2 and PA formation. We further demonstrate that PA and PI(3,5)P2 are also required for the ATP13A2-mediated protection against the toxic metals Mn2+, Zn2+, and Fe3+, suggesting a general lipid-dependent activation mechanism of ATP13A2 in various PD-related stress conditions. Our results indicate that the ATP13A2-mediated protection requires binding of PI(3,5)P2 to LBS2 and PA to LBS3. Thus, targeting the N-terminal lipid binding sites of ATP13A2 might offer a therapeutic approach to reduce cellular toxicity of various PD insults including mitochondrial stress.

Mutated ATP10B increases Parkinson’s disease risk by compromising lysosomal glucosylceramide export

“…Significance was assessed by one-way ANOVA with either Dunnett's post hoc (e, to Rab11; a, c to mirFluc) or Tukey's (g, i) post hoc whereby, 1 mark P < 0.05, 2 marks P < 0.01, 3 marks P < 0.001, 4 marks P < 0.0001 linked to PD [28,90]. As a lysosomal polyamine exporter, ATP13A2 provides protection to rotenone and MnCl 2 [68,111,112], and also maintains lysosomal functionality and membrane integrity [111], pointing to a remarkable synergy between the two lysosomal export systems. Rotenone is a mitochondrial complex I inhibitor, whereas MnCl 2 may inhibit the mitochondrial respiratory chain at the level of complex II [43,102].…”

“…To investigate whether ATP10B exerts a cell protective effect, stable cell lines were exposed to the heavy metals MnCl 2 and ZnCl 2 , the 26S proteasome inhibitor bortezomib and the mitochondrial complex I inhibitor rotenone, stressors that evoked a phenotype in cell models of ATP13A2 loss of function, another late endo-lysosomal P-type ATPase implicated in PD [26,48,68]. ATP10B WT significantly protected HeLa cells against rotenone and MnCl 2 , but not against ZnCl 2 or Bortezomib (Fig.…”

Toxic-Metal-Induced Alteration in miRNA Expression Profile as a Proposed Mechanism for Disease Development

“…The dopaminergic system is very sensitive to Mn toxicity and is a target for elevated Mn concentrations in welders using Mn-containing flux [127]. Mn toxicity involves the generation of free radicals and alterations in normal mitochondrial function [2,128,129].…”

Impulse control disorder, lysosomal malfunction andATP13A2 insufficiency in Parkinsonism

“…Failure of mitochondrial maintenance and regulation is involved in PD pathogenesis . Notably, ATP13A2 deficiency has been shown to contribute mitochondrial dysfunction and one of the mechanisms in mediating mitochondrial dyshomeostasis is compromised autophagy . ATP13A2 deficiency has been shown to be associated with MYCBP2‐induced ubiquitination of TSC2, leading to Rheb GTPase in a GTP‐bound conformation and mTORC1 activation on lysosomes, thereby inhibition of TFEB‐mediated lysosomal gene transcriptions and inhibition of autophagy (Figure ).…”

“…Since ATP13A2 might interact with synaptotagmin‐11 encoded by SYT11 that is mutated in PD and regulates autophagy in the same pathway as ATP13A2, and synaptotagmins bind a series of different cations, it is also possible that synaptotagmin‐11 regulates ATP13A2 transport efficiency. In addition, ATP13A2 contains a unique N‐terminal hydrophobic extension on the lysosomal cytosolic membrane surface to interact with phosphatidic acid (PA) and phosphatidylinositol(3,5)bisphosphate [PI(3,5)P2] that stimulate ATP13A2 auto‐phosphorylation and are required for the ATP13A2‐mediated protection against the toxic metals Mn 2+ , Zn 2+ , and Fe 3+ (Figure ). ATP13A2 deficiency results in neuronal ceroid lipofuscinosis including accumulation of lipofuscin positive for subunit c of mitochondrial ATP synthase, suggesting that a common pathogenic mechanism underlies both neuronal ceroid lipofuscinosis and Parkinson's disease .…”