SNCA and multiple system atrophy: Detergent-insoluble phosphorylated α-synuclein oligomers as well as SDS- and formic acid-extractable phosphorylated α-synuclein, including oligomeric species, were found in the brains of bigenic mice Tg(M83+/−:Gfap-luc) inoculated with TgM83+/+ or MSA brain homogenates.