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Biomedical subjects

Christoph B Lücking

Publications and source records attributed to Christoph B Lücking.

7 recordsLinked to original sources
PubMed2005

Mutations in the pantothenate kinase gene PANK2 are not associated with Parkinson disease.

Pantothenate kinase-associated neurodegeneration (PKAN) may serve as a model for Parkinson disease (PD) since many PKAN patients suffer from parkinsonism and both conditions lead to iron accumulation in the basal ganglia. We screened the gene coding for pantothenate kinase 2 (PANK2) for sequence variants in PD. We found no mutations in 67 PD patients with affected sibs or early-onset disease. Moreover, PANK2 polymorphisms were not associated with late-onset idiopathic PD in 339 patients. We conclude that PANK2 variants exert, if any, only a very small effect in the genetic risk of PD.

Case-Control Studies↗
PubMed2003

Parkin prevents mitochondrial swelling and cytochrome c release in mitochondria-dependent cell death.

Parkin gene mutations have been implicated in autosomal-recessive early-onset parkinsonism and lead to specific degeneration of dopaminergic neurons in midbrain. To investigate the role of Parkin in neuronal cell death, we overproduced this protein in PC12 cells in an inducible manner. In this cell line, neuronally differentiated by nerve growth factor, Parkin overproduction protected against cell death mediated by ceramide, but not by a variety of other cell death inducers (H(2)O(2), 4-hydroxynonenal, rotenone, 6-OHDA, tunicamycin, 2-mercaptoethanol and staurosporine). Protection was abrogated by the proteasome inhibitor epoxomicin and disease-causing variants, indicating that it was mediated by the E3 ubiquitin ligase activity of Parkin. Interestingly, Parkin acted by delaying mitochondrial swelling and subsequent cytochrome c release and caspase-3 activation observed in ceramide-mediated cell death. Subcellular fractionation demonstrated enrichment of Parkin in the mitochondrial fraction and its association with the outer mitochondrial membrane. Together, these results suggest that Parkin may promote the degradation of substrates localized in mitochondria and involved in the late mitochondrial phase of ceramide-mediated cell death. Loss of this function may underlie the degeneration of nigral dopaminergic neurons in patients with Parkin mutations.

Animals↗
PubMed2003

Mutation analysis of the parkin gene in Russian families with autosomal recessive juvenile parkinsonism.

Autosomal recessive juvenile parkinsonism (AR-JP) is a form of hereditary parkinsonism characterized by variable clinical presentations and caused by mutations in a novel gene, parkin, on chromosome 6q25.2-27. Until now, no Russian cases of parkin-associated AR-JP have been reported on. We recruited 16 patients from 11 Russian families with dopa-responsive movement disorders according to the following criteria: 1) family history compatible with autosomal recessive inheritance; 2) onset of symptoms at </=30 years of age; and 3) the lack of mutations in the GTP cyclohydrolase I gene (in sporadic cases). Mutation screening of the parkin gene was carried out by a semiquantitative PCR assay and direct sequencing of the coding region. Six different parkin mutations (both deletions and point mutations) were identified in the index cases from four families, including a novel point mutation in the donor splice site (IVS1+1G-->A). The majority of our parkin-associated cases were characterized by early-onset dopa-responsive parkinsonism with benign course and slow progression (5 patients from two families have been followed for as long as 18-36 years), and 1 patient had a phenotype of dopa-responsive dystonia. This first description of Russian patients with AR-JP and molecularly proven parkin mutations confirms the widespread occurrence of this polymorphic hereditary extrapyramidal disorder.

Adult↗
PubMed2003

The C289G and C418R missense mutations cause rapid sequestration of human Parkin into insoluble aggregates.

Mutations in the parkin gene are responsible for autosomal recessive parkinsonism. The disease-linked missense mutations are highly concentrated in the RING-IBR-RING domains of Parkin. In this study, we investigated the consequences of several missense parkin gene mutations in cell culture. We have demonstrated that two of these mutations (C289G and C418R), which replace consensus cysteine residues in the RING domains, significantly decrease the solubility of Parkin in cells. Upon overexpression, the presumably misfolded proteins formed cytoplasmic aggregates that concentrated into large perinuclear inclusion bodies when proteasome activity was inhibited. This process required active microtubule-dependent retrograde transport, as previously reported for aggresome formation. These results provide information on the molecular basis of the loss of function caused by mutations of critical residues in Parkin. They also contribute to our understanding of the cellular mechanism underlying the aggregation of mutant Parkin.

Animals↗
PubMed2002

Complex relationship between Parkin mutations and Parkinson disease.

Mutations in the Parkin gene cause juvenile and early onset Parkinsonism. While Parkin-related disease is presumed to be an autosomal-recessive disorder, cases have been reported where only a single Parkin allele is mutated and raise the possibility of a dominant effect. In this report, we re-evaluate twenty heterozygous cases and extend the mutation screening to include the promoter and intron/exon boundaries. Novel deletion, point and intronic splice site mutations are described, along with promoter variation. These data, coupled with a complete review of published Parkin mutations, confirms that not only is recessive loss of Parkin a risk factor for juvenile and early onset Parkinsonism but that Parkin haplo-insufficiency may be sufficient for disease in some cases.

Adolescent↗