Publications

• Functions of potA and potD proteins in spermidine-preferential uptake system in Escherichia coli.

  Kashiwagi K., Miyamoto S., Nukui E., Kobayashi H., Igarashi K.

  Functions of potA and -D proteins in the spermidine-preferential uptake system, which consists of potA, -B, -C, and -D proteins, were studied. Spermidine uptake activity was lost when the gene for potA or potD protein was disrupted, and transformation of the cells with potA or potD gene recovered ... >> More

  Functions of potA and -D proteins in the spermidine-preferential uptake system, which consists of potA, -B, -C, and -D proteins, were studied. Spermidine uptake activity was lost when the gene for potA or potD protein was disrupted, and transformation of the cells with potA or potD gene recovered the uptake activity. PotD protein was found to bind spermidine with a 3.2 microM dissociation constant. Spermidine uptake by membrane vesicles prepared from Escherichia coli DR112 containing the genes for potA, -B, and -C proteins was strongly dependent on the addition of potD protein, and its optimal concentration was 5 microM when 10 microM spermidine was used as substrate. The ATP dependence of spermidine uptake was examined with the atp mutant of E. coli. The uptake was completely dependent on ATP. When the membrane potential was extinguished by carbonyl cyanide m-chlorophenylhydrazone, the uptake activity was decreased by 60% even if ATP existed. This suggests that the membrane potential is also involved in the spermidine uptake. ATP was found to bind to potA protein. In the spermidine transport-deficient mutant E. coli NH1596, valine 135 of potA protein, which is located between two consensus amino acid sequences for nucleotide binding, was replaced by methionine. Although the amount of mutated potA protein expressed in E. coli cells was the same as that of normal potA protein and the mutated protein was membrane-associated, no significant spermidine uptake was observed. The results taken together indicate that potA and -D proteins are absolutely necessary for spermidine uptake in conjunction with the two channel forming proteins (potB and -C). << Less

  J. Biol. Chem. 268:19358-19363(1993) [PubMed] [EuropePMC]

• ATP13A2 deficiency disrupts lysosomal polyamine export.

  van Veen S., Martin S., Van den Haute C., Benoy V., Lyons J., Vanhoutte R., Kahler J.P., Decuypere J.P., Gelders G., Lambie E., Zielich J., Swinnen J.V., Annaert W., Agostinis P., Ghesquiere B., Verhelst S., Baekelandt V., Eggermont J., Vangheluwe P.

  ATP13A2 (PARK9) is a late endolysosomal transporter that is genetically implicated in a spectrum of neurodegenerative disorders, including Kufor-Rakeb syndrome-a parkinsonism with dementia¹-and early-onset Parkinson's disease². ATP13A2 offers protection against genetic and en ... >> More

  ATP13A2 (PARK9) is a late endolysosomal transporter that is genetically implicated in a spectrum of neurodegenerative disorders, including Kufor-Rakeb syndrome-a parkinsonism with dementia¹-and early-onset Parkinson's disease². ATP13A2 offers protection against genetic and environmental risk factors of Parkinson's disease, whereas loss of ATP13A2 compromises lysosomes³. However, the transport function of ATP13A2 in lysosomes remains unclear. Here we establish ATP13A2 as a lysosomal polyamine exporter that shows the highest affinity for spermine among the polyamines examined. Polyamines stimulate the activity of purified ATP13A2, whereas ATP13A2 mutants that are implicated in disease are functionally impaired to a degree that correlates with the disease phenotype. ATP13A2 promotes the cellular uptake of polyamines by endocytosis and transports them into the cytosol, highlighting a role for endolysosomes in the uptake of polyamines into cells. At high concentrations polyamines induce cell toxicity, which is exacerbated by ATP13A2 loss due to lysosomal dysfunction, lysosomal rupture and cathepsin B activation. This phenotype is recapitulated in neurons and nematodes with impaired expression of ATP13A2 or its orthologues. We present defective lysosomal polyamine export as a mechanism for lysosome-dependent cell death that may be implicated in neurodegeneration, and shed light on the molecular identity of the mammalian polyamine transport system. << Less

  Nature 578:419-424(2020) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.