Additional file 1.

Proteolytic network in specific brain regions of Ctsk-/- mice as compared to WT controls. Densitometry analysis of immunoblots and results of cathepsin activity assays performed with brain tissue lysates of WT (open bars) and Ctsk-/- mice (grey bars) (A-D, A'-D') Cathepsin D protein levels were unaltered and its activity as determined by cleavage of MOCAc-Gly-Lys-Pro-Ile-Leu-Phe ~ Phe-Arg-Leu-Lys (Dnp)-D-Arg-NH2 at pH 4.0 was slightly elevated in cerebellum of Ctsk-/- mice, but these changes were not significant (A, Ctsk-/- n = 20, WT n = 19; A', Ctsk-/- n = 5, WT n = 5; B, Ctsk-/- n = 15, WT n = 17; B', Ctsk-/- n = 5, WT n = 5; C, Ctsk-/- n = 16, WT n = 17; C', Ctsk-/- n = 5, WT n = 5; D, Ctsk-/- n = 8, WT n = 12; D', Ctsk-/- n = 5, WT n = 5). (E-H, E'-H') Cathepsin B protein levels were decreased in cerebral cortex of Ctsk-/- mice, while its activity as determined by cleavage of Z-Arg-Arg-AMC at pH 6.0 was reduced only in striatum/mesencephalon of these mice (E, Ctsk-/- n = 18, WT n = 19; E', Ctsk-/- n = 5, WT n = 5; F, Ctsk-/- n = 14, WT n = 15; F', Ctsk-/- n = 8, WT n = 8; G, Ctsk-/- n = 16, WT n = 18; G', Ctsk-/- n = 5, WT n = 5; H, Ctsk-/- n = 13, WT n = 17; H', Ctsk-/- n = 5, WT n = 5). (I-L, I'-L') Cathepsin L protein levels were down-regulated in cerebral cortex, while its Z-Phe-Arg-AMC cleaving activity at pH 5.5 was decreased in striatum/mesencephalon (I, Ctsk-/- n = 19, WT n = 19; I', Ctsk-/- n = 5, WT n = 5; J, Ctsk-/- n = 13, WT n = 15; J', Ctsk-/- n = 8, WT n = 8; K, Ctsk-/- n = 16, WT n = 18; K', Ctsk-/- n = 5, WT n = 5; L, Ctsk-/- n = 13, WT n = 17; L', Ctsk-/- n = 5, WT n = 5). (M-P) Protein levels of the endogenous cysteine peptidase inhibitor, cystatin C, were significantly upregulated in striatum/mesencephalon and hippocampus of Ctsk-/- mice (M, Ctsk-/- n = 15, WT n = 17; N, Ctsk-/- n = 14, WT n = 12; O, Ctsk-/- n = 14, WT n = 17; P, Ctsk-/- n = 17, WT n = 16). The results indicated deregulated cysteine cathepsins B and L and cystatin C levels depending on the particular brain region analyzed in Ctsk-/- mice, whereas the neuroprotective aspartic protease cathepsin D remained unaffected. Levels of significance are denoted as * for p < 0.05; ** for p < 0.01; *** for p < 0.001.

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Dauth et al. BMC Neuroscience 2011 12:74   doi:10.1186/1471-2202-12-74