Figure 1: Altered expression of Lamp1 in the brain of Neu1^−/− mice.

(a) Neu1 expression is high in the CA3 region of the WT hippocampus. (b) Oversialylation of Lamp1 shown on immunoblots of WT and Neu1^−/− hippocampal lysates probed with the indicated antibody. (c) Loss of Neu1 is accompanied by accumulation of Lamp1. (d) Extent of lysosomal exocytosis measured as β-hex enzyme activity in the culture medium of neurospheres. Neu1^−/−/Arf hippocampal neurospheres have enhanced lysosomal exocytosis. (e) Representative picture of WT^Arf and Neu1^−/−/Arf hippocampal neurons stained with β-III tubulin (green) and glial fibrillary acidic protein (GFAP; red). (f) Neu1^−/−/Arf hippocampal neurons have enhanced lysosomal exocytosis as assessed by β-hex enzyme activity measured in the culture medium. Asterisks indicate statistically significant results, as determined by the Student’s t-test. Data are represented as mean±s.d. (error bars); n=3. Mice used for histological analyses were 5 months of age. Scale bars, 20 μm.