Figure 8.

Colocalization of Nrxns with additional presynaptic components on transport vesicles. Hippocampal neurons were transfected with N-EGFP-Nrxn1α alone (A–F; J–L), or cotransfected with N-EGFP-Nrxn1α and HA-tagged N-type calcium channel along with α2δ and β1b subunits) (G–I). Nrxn was visualized by its EGFP tag (autofluorescence; B, E, H, K), and endogenous or transfected proteins were labeled with appropriate antibodies (red), with colocalization appearing yellow in the merged pictures (C, F, I, L). Colocalization is seen between nonsynaptic Nrxn1α and CASK (C), RIM1α (F), and HA-tagged N-type calcium channels (I), but not between Nrxn1α and Mint1 (L, open-headed arrows). M, Quantification of colocalization between Nrxn1α and CASK, RIM1α, N-type calcium channel, or Mint1. Scale bar, 20 μm.