Figure 2

Menin is cleaved by calpain. (A) ICC localization of menin in hippocampal cultures at DIV 7, cultured in the presence of 0.1% DMSO vehicle control (i–v) or 20 μM PD150606 (vi–x), a cell permeable calpain inhibitor (n = 9 images, 3 independent samples each, representative images). Cells were labeled with the nuclear stain DAPI (i,vi), menin N-terminal (ii,vii) and C-terminal (iii,viii) epitope antibodies, and a neurofilament antibody (iv,ix), (v,x) shows merged channels. Scale bar, 50 μm. (B) Enlarged region of interest (ROI) depicting neurite structure from the boxed region shown in Av (i–iii) and Ax (iv–vi). Scale bar, 10 μm. (C,D) Summary data, fluorescence intensity of the nuclear α-N-menin signal was unaffected (C; ROIs: 0.1% DMSO n = 67, 20 μM PD150606 n = 59), whereas the neurite α-C-menin signal was reduced upon calpain inhibition (D; ROIs: n = 27 each). ***Statistical significance (independent t-test), P < 0.001. See also Table S1 and Figs S1 and S2.