Fig. 1

CNTNAP2 is cleaved by α-secretase and furin. a, b ADAM10 and ADAM17 cleaved mature CNTNAP2 (mCNT) in HEK cells. HEK cells were co-transfected with CNTNAP2 and empty vector, ADAM10 or ADAM17 plasmids, and harvested 24 h after transfection for Western Blot analysis. Non-transfected HEK (NT HEK) was used as a negative control. CTFα1 and CTFα2 were increased/generated by ADAM10 and ADAM17. n = 4 independent experiments, ordinary one-way ANOVA followed by Dunnett’s multiple comparisons test, *p < 0.05; **p < 0.01; ***p < 0.001. c, d ADAM10 is the major α-secretase that generates CTFα1. CNTNAP2 was co-transfected with GFP into HEK, ADAM10-knockout (KO), or ADAM17-KO HEK cells. The CTFα1/mCNT ratio was reduced in ADAM10-KO cells while increased in ADAM17-KO cells. n = 3 independent experiments, unpaired t-test, **p < 0.01. e, f Furin cleaved mature CNTNAP2 in HEK cells. HEK cells were co-transfected with CNTNAP2 and vector or furin. CTFf at 55 kDa was increased by furin. n = 3 independent experiments, unpaired t-test, *p < 0.05. g CNTNAP2 on the cell membrane was cleaved in HEK and N2a cells. CNTNAP2 was co-transfected with vector (myc), ADAM10, ADAM17, or furin plasmids into HEK and N2a cells. Cells were fixed 24 h after transfection, and immunocytochemistry (ICC) was performed. CNTNAP2 was detected by an anti-CNTNAP2 antibody targeting the N-terminal 1001–1042 aa outside the cell membrane. CNTNAP2 was mainly expressed on the cell membrane and was reduced by co-transfected plasmids. Images were acquired using Zeiss Apotome to reflect the morphology. Scale bar represents 50 μm. h Quantification of ICC in HEK and N2a. CNTNAP2 mean intensity was measured using the corresponding conventional fluorescence images in Supplementary Fig. 2. n = 10 cells from 2 independent experiments, ordinary one-way ANOVA followed by Dunnett’s multiple comparisons test, ****p < 0.0001. All the results are expressed as mean ± SEM