The Protein Complex of Neurodegeneration-related Phosphoinositide Phosphatase Sac3 and ArPIKfyve Binds the Lewy Body-associated Synphilin-1, Preventing Its Aggregation
| Autor: | Xuequn Chen, Lauren M. Compton, Ellen J. Tisdale, Ognian C. Ikonomov, Assia Shisheva, Diego Sbrissa, Rita Kumar |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Scaffold protein
endocrine system Green Fluorescent Proteins Phosphatase Nerve Tissue Proteins macromolecular substances Biology Biochemistry PIKFYVE Chlorocebus aethiops medicine Animals Humans Molecular Biology Ternary complex Flavoproteins Lewy body Neurodegeneration Intracellular Signaling Peptides and Proteins Membrane Proteins Neurodegenerative Diseases Molecular Bases of Disease Cell Biology medicine.disease Phosphoric Monoester Hydrolases Cell biology HEK293 Cells Aggresome Proteasome COS Cells Lewy Bodies Carrier Proteins Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 290:28515-28529 |
| ISSN: | 0021-9258 |
| Popis: | The 5-phosphoinositide phosphatase Sac3, in which loss-of-function mutations are linked to neurodegenerative disorders, forms a stable cytosolic complex with the scaffolding protein ArPIKfyve. The ArPIKfyve-Sac3 heterodimer interacts with the phosphoinositide 5-kinase PIKfyve in a ubiquitous ternary complex that couples PtdIns(3,5)P2 synthesis with turnover at endosomal membranes, thereby regulating the housekeeping endocytic transport in eukaryotes. Neuron-specific associations of the ArPIKfyve-Sac3 heterodimer, which may shed light on the neuropathological mechanisms triggered by Sac3 dysfunction, are unknown. Here we conducted mass spectrometry analysis for brain-derived interactors of ArPIKfyve-Sac3 and unraveled the α-synuclein-interacting protein Synphilin-1 (Sph1) as a new component of the ArPIKfyve-Sac3 complex. Sph1, a predominantly neuronal protein that facilitates aggregation of α-synuclein, is a major component of Lewy body inclusions in neurodegenerative α-synucleinopathies. Modulations in ArPIKfyve/Sac3 protein levels by RNA silencing or overexpression in several mammalian cell lines, including human neuronal SH-SY5Y or primary mouse cortical neurons, revealed that the ArPIKfyve-Sac3 complex specifically altered the aggregation properties of Sph1-GFP. This effect required an active Sac3 phosphatase and proceeded through mechanisms that involved increased Sph1-GFP partitioning into the cytosol and removal of Sph1-GFP aggregates by basal autophagy but not by the proteasomal system. If uncoupled from ArPIKfyve elevation, overexpressed Sac3 readily aggregated, markedly enhancing the aggregation potential of Sph1-GFP. These data identify a novel role of the ArPIKfyve-Sac3 complex in the mechanisms controlling aggregate formation of Sph1 and suggest that Sac3 protein deficiency or overproduction may facilitate aggregation of aggregation-prone proteins, thereby precipitating the onset of multiple neuronal disorders. |
| Databáze: | OpenAIRE |
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