Figure 4.

Proteasomal Saturation in Endophilin Mutant Mice

(A–C) Western blots for polyubiquitin (A), K48 linked (B; proteasome targeting), and K63 linked (C; proteasome unrelated) in 1,2 DKO cortex. (Right) Quantification is shown (min. six samples/genotype). ^∗p < 0.05; ^∗∗p < 0.01; Student’s t test; mean ± SEM.

(D and E) TKO MEFS (D) or neurons (E) transfected with ubiquitin-G76V-GFP (modified GFP targeted for proteasomal degradation). The scale bar represents 10 μm. (Right) Quantification of GFP fluorescence is shown. In MEFs, proteasome inhibitor MG132 was used as control. ^∗p < 0.05; Student’s t test; mean ± SEM.

(F) Proteasomal activity (chymotrypsin-like) in brain extracts of TKOs relative to littermate controls. p > 0.05; Student’s t test; mean ± SEM.

(G) Activity of caspases 3 and 7 reveals that apoptosis is increased in TKO MEFs transfected with ubiquitin-G76V-GFP. ^∗∗∗p < 0.001; Student’s t test; mean ± SD.

See also Figure S3.