Table 3.

Summary of experiments investigating parkin function on $\alpha$-synuclein-induced toxicity in vivo and in vitro.

References	Method	Organism	Finding	$\mathbf{Parkin}\mathbf{and}\mathit{\alpha }$
[217]	Overexpression of parkin with A53T and A30P mutated $\alpha$-synuclein	Primary cell culture	Increased parkin expression can mitigate mutated $\alpha$-synuclein induced toxicity.	Yes
[227]	Quantification of wild-type $\alpha$-synuclein pathology in parkin−/− mice	Mouse model	No loss of nigral dopaminergic neurons and no accumulation of $\alpha$-synuclein.	No
[218]	Co-expression of parkin with A53T, A30P, or wild-type $\alpha$-synuclein	Drosophila melanogaster	Increased parkin expression can mitigate mutated $\alpha$-synuclein induced toxicity.	Yes
[219]	Co-expression of parkin with wild-type $\alpha$-synuclein.	Drosophila melanogaster	Increased parkin expression can suppress $\alpha$-synuclein-induced loss of climbing ability.	Yes
[228]	Quantification of wild-type $\alpha$-synuclein pathology in parkin−/− mice	Mouse mutant quaking (viable) model	No loss of dopaminergic neurons and no accumulation of $\alpha$-synuclein.	No
[220]	Overexpression of wild-type rat parkin with human A30P $\alpha$-synuclein using lentiviral vector delivery.	Rat model	Increased parkin expression can significantly reduce $\alpha$-synuclein-induced neuropathology.	Yes
[229]	Quantification of wild-type $\alpha$-synuclein pathology in parkin−/− mice	Mouse model	No accumulation of $\alpha$-synuclein.	No
[221]	Overexpression of human wild-type $\alpha$-synuclein and human parkin in the substantia nigra in rats using rAAV vector	Rat model	Increased parkin expression can mitigate $\alpha$-synuclein induced toxicity.	Yes
[222]	Co-expression of parkin with A30P $\alpha$-synuclein.	Drosophila melanogaster	Increased expression of parkin could counteract the effect of A30P mutated $\alpha$-synuclein.	Yes
[230]	Overexpression of human A53T $\alpha$-synuclein and deletion of parkin.	Mouse model	No effect of loss of parkin on neuropathology.	No
[223]	Co-expression of parkin with wild-type $\alpha$-synuclein.	Macaque monkeys.	Overexpression of parkin was associated with less accumulation of $\alpha$-synuclein and phosphorylation at S129.	Yes
[224]	A transgenic mouse model expressing human A30P $\alpha$-synuclein and no parkin.	Mouse model	A lower amount of pSer129 $\alpha$-synuclein in parkin−/− mice compared with parkin+/+ mice.	Yes
[182]	Co-expression of parkin with wild-type $\alpha$-synuclein.	Sprague Dawley rats	Increased expression of parkin resulted in a decreased expression of pSer87 and pSer129 $\alpha$-synuclein.	Yes
[225]	Overexpression of human wild-type $\alpha$-synuclein by rAAV vectors in parkin−/− and wild type mice.	Mouse model	Increased pSer129 $\alpha$-synuclein but no loss of dopaminergic neurons in parkin knockout mice.	Yes
[226]	Addition of exogenous $\alpha$-synuclein oligomers in a primary cell culture with a parkin knock-down or overexpression.	Rat pheochromocytoma (PC12) cells	Parkin overexpression protected against the extracellular $\alpha$-synuclein oligomer-mediated toxicity.	Yes