Identification and characterization of a novel endogenous murine parkin mutation.
Various mutations in the PARK2 gene which encodes the protein, parkin, are causal of a disease entity-termed autosomal recessive juvenile parkinsonism. Parkin can function as an E3 ubiquitin-protein ligase, mediating the ubiquitination of specific targeted proteins and resulting in proteasomal degradation. Parkin is thought to lead to parkinsonism as a consequence of a loss in its function. In this study, immunoblot analyses of brain extracts from Balb/c, C57BL/6, C3H, and 129S mouse strains demonstrated significant variations in immunoreactivity with anti-parkin monoclonal antibodies (PRK8, PRK28, and PRK109). This resulted partly from differences in the steady-state levels of parkin protein across mouse strains. There was also a complete loss of immunoreactivity for PRK8 and PRK28 antibodies in C3H mice due to was because of a homologous nucleotide mutation resulting in an E398Q amino acid substitution. In cultured cells, parkin harboring this mutation had a greater tendency to aggregate, exhibited reduced interaction with the E2 ubiquitin-conjugating enzymes, UbcH7 and UbcH8, and demonstrated loss-of-function in promoting the proteosomal degradation of a specific putative substrate, synphilin-1. In situ, C3H mice displayed age-dependent increased levels of brain cortical synphilin-1 compared with C57BL/6, suggesting that E398Q parkin in these mice is functionally impaired and that C3H mice may be a suitable model of parkin loss-of-function similar to patients with missense mutations.
Ramsey
Chenere P
CP
Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6084, USA.
Giasson
Benoit I
BI
D000818:Animals; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004252:DNA Mutational Analysis / Q000379:methods; D018604:Epitope Mapping / Q000379:methods; D005786:Gene Expression Regulation / Q000235:genetics*; D018698:Glutamic Acid / Q000235:genetics; D005973:Glutamine / Q000235:genetics; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013045:Species Specificity; D014162:Transfection / Q000379:methods; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism*; D054875:Ubiquitination
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C498464:Sncaip protein, mouse; D005973:Glutamine; D018698:Glutamic Acid; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein