Accumulation of neurexin-CTFs in synaptic fractions of PS cDKO mice.

A) Brain lysates from PS1+/+, PS1+/− and PS1−/− mouse embryos (E 17.5) or 2 month-old control wild-type (WT) and PS cDKO mice were analyzed by Western blotting with the cyto-neurexin (Nrx), PS1 and N-cadherin (N-cadh) antibodies, as indicated. Neurexin-CTFs and N-cadherin-CTF levels increased coinciding with decreased PS1 expression in animals lacking PS. The results were replicated in at least two independent mice per condition, as shown. B) Accumulation of neurexin-CTFs in purified synaptosomal and synaptic fractions from PS cDKO mice. Cortical brain lysates and pre- and post-synaptic fractions obtained from synaptosomal preparations from control wild-type (WT) and PS cDKO mice were analyzed by Western blotting with the cyto-neurexin, PS1, synaptophysin (SYP) and PSD95 antibodies. Neurexin-CTFs levels are markedly increased in synaptosomes and presynaptic fractions of PS cDKO mice. Synaptophysin and PSD-95 are specifically enriched in the presynaptic and postsynaptic fractions, respectively.