b, Accumulation of Triton-X-100-solublepolyubiquitinated proteins in the brains of Atg5flox/flox; nestin-Cre mice. Brain homogenate prepared at the indicated times from control (Atg5flox/+; nestin-Cre) and Atg5flox/flox; nestin-Cre (Atg5flox/flox) mice were separated into Triton-X-100-soluble (S) and -insoluble (P) fractions and analysed by immunoblotting using anti-ubiquitin antibodies. Arrowhead indicates the stacking gel. 