A, B. C-terminal CFP fusions of neurexins 1β, 2'β, 3'β, 1α, 2α and 3α (+S4) or (−S4) were expressed in COS7 cells and visualized by CFP fluorescence. Cells were incubated with ectodomain fusions. LRRTM2-AP (A) bound specifically to all (−S4) neurexin isoforms. NLG1-AP (B) bound to all β isoforms of neurexins, regardless of S4 variant, and did not bind to any α isoforms. Scale bar, 10µm.
C. Quantitation of the data in panel A, normalised to Nrxβ(−S4)-CFP. (ANOVA p<0.0001, n=60 cells each, posthoc Tukey’s test *p<0.001, comparison to control, results are expressed as mean ± SEM). Data for neurexins 1, 2 and 3 were pooled.
D. Quantitation of the data in panel B, normalised to Nrxβ(−S4)-CFP (ANOVA p<0.0001, n=30 cells each, posthoc Tukey’s test *p<0.001 comparison to control, p<0.01 between Nrxβ (−S4) and (+S4), results are expressed as mean ± SEM). Data for neurexins 1, 2 and 3 were pooled.