title: Synaptojanin 1 mutation in Parkinson's disease brings further insight into the neuropathological mechanisms.
abstract: Synaptojanin 1 (SYNJ1) is a phosphoinositide phosphatase highly expressed in nerve terminals. Its two phosphatase domains dephosphorylate phosphoinositides present in membranes, while its proline-rich domain directs protein-protein interactions with synaptic components, leading to efficient recycling of synaptic vesicles in neurons. Triplication of SYNJ1 in Down's syndrome is responsible for higher level of phosphoinositides, enlarged endosomes, and learning deficits. SYNJ1 downregulation in Alzheimer's disease models is protective towards amyloid-beta peptide (Aβ) toxicity. One missense mutation in one of SYNJ1 functional domains was recently incriminated in an autosomal recessive form of early-onset Parkinson's disease (PD). In the third decade of life, these patients develop progressive Parkinsonism with bradykinesia, dystonia, and variable atypical symptoms such as cognitive decline, seizures, and eyelid apraxia. The identification of this new gene, together with the fact that most of the known PD proteins play a role in synaptic vesicle recycling and lipid metabolism, points out that synaptic maintenance is a key player in PD pathological mechanisms. Studying PD genes as a network regulating synaptic activity could bring insight into understanding the neuropathological processes of PD and help identify new genes at fault in this devastating disorder.
authors.affiliation: Sorbonne Universités, UPMC (Paris 6), UMR S 1127, Inserm U 1127, CNRS UMR 7225, and ICM, 75013 Paris, France ; Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle Epinière ICM, 4ème Étage, 47 Boulevard de l'Hôpital, 75651 Paris, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Drouet
authors.affiliation: Sorbonne Universités, UPMC (Paris 6), UMR S 1127, Inserm U 1127, CNRS UMR 7225, and ICM, 75013 Paris, France.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Lesage
mesh_terms: D001483:Base Sequence; D001921:Brain / Q000503:physiopathology*; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010300:Parkinson Disease / Q000503:physiopathology*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D015995:Prevalence; D000099182:Phosphoinositide 5-Phosphatases
chemical_list: D005819:Genetic Markers; D010744:Phosphoric Monoester Hydrolases; D000099182:Phosphoinositide 5-Phosphatases