MPP2 is not expressed at classical inhibitory synapses.

(a) Confocal imaging maximum projection of primary rat hippocampal neurons fixed at DIV21 and stained for endogenous proteins MPP2 (cyan) together with the inhibitory postsynaptic scaffold protein Gephyrin (magenta) and the inhibitory presynaptic marker VGAT (yellow). White box indicates region of detail view in b and c. Scale bar: 10 μm. (b, c) Detail view of region indicated in a. MPP2 is clearly enriched in dendritic spines along neuronal dendrites (which have lower MPP2 expression) and generally distinct from inhibitory synapses (arrowheads) as marked by Gephyrin staining with directly adjacent VGAT. MPP2 and Gephyrin staining does not significantly overlap, but occasionally MPP2-positive spines have adjacent VGAT puncta (arrows). Scale bar: 5 μm. DIV, days in vitro; MPP2, membrane protein palmitoylated 2.