TPO and multiple system atrophy: Here, the A53E mutation blocked MSA prion replication (P = 0.54, i.c.; P = 0.18, sc.n.; Fig 5E) whereas samples from MSA-inoculated mice caused significant infection in the α-syn140*A53T-YFP and α-syn140*A53V-YFP cells, regardless of inoculation route (P < 0.05; Fig 5F and 5G).