title: Parkin regulates metal transport via proteasomal degradation of the 1B isoforms of divalent metal transporter 1.
abstract: Abnormal iron accumulation is linked to a variety of neurological disorders and may contribute to the progressive damage seen in these diseases. The biochemical processes responsible for iron accumulation are not known but are likely to entail alteration in transport into injured brain areas. The major transport protein responsible for uptake of iron is divalent metal transporter 1 (DMT1) and recent studies demonstrate that the 1B species is regulated post-translationally by degradation via the proteasomal pathway. As reported in this paper, the E3 ligase, parkin, when over-expressed in SH-SY5Y cells, results in a decrease in 1B-DMT1 isoforms and also a significant reduction in manganese transport and toxicity. Incubating cells over-expressing parkin with the proteasomal inhibitor, MG-132, restores 1B-DMT1 levels emphasizing that the observed changes are caused by degradation via the proteasomal pathway. Expression of the 1B species of DMT1 was also shown to be elevated in human lymphocytes containing a homozygous deletion of exon 4 of parkin and in brains of parkin knockout animals. Immunoprecipitation and immunofluorescent studies confirm that parkin co-localizes with DMT1 in SH-SY5Y cells transfected with wild-type parkin. These results demonstrate that parkin is the E3 ligase responsible for ubiquitination of the 1B species of DMT1.
authors.affiliation: Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214, USA. jaroth@buffalo.edu
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Roth
authors.forename: Steven
authors.initials: S
authors.lastname: Singleton
authors.forename: Jian
authors.initials: J
authors.lastname: Feng
authors.forename: Michael
authors.initials: M
authors.lastname: Garrick
authors.forename: Prasad N
authors.initials: PN
authors.lastname: Paradkar
mesh_terms: D000328:Adult; D000818:Animals; D001402:B-Lymphocytes; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002712:Chlorides / Q000494:pharmacology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D005091:Exons / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D007976:Leupeptins / Q000494:pharmacology; D008297:Male; D008345:Manganese / Q000378:metabolism; D017895:Manganese Compounds / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000502:physiology; D009447:Neuroblastoma / Q000473:pathology; D010300:Parkinson Disease / Q000473:pathology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D014162:Transfection / Q000379:methods; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D027682:Cation Transport Proteins; D002712:Chlorides; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D008345:Manganese; D017895:Manganese Compounds; D046988:Proteasome Endopeptidase Complex; D020033:Protein Isoforms; D044767:Ubiquitin-Protein Ligases; D000099236:Solute Carrier Family 11, Member 2; C111567:parkin protein; C025340:manganese chloride; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde