Muskelin puncta in dendrites partially colocalize with SV2-positive presynaptic axon terminals. (A) Detection of endogenous muskelin in cultured hippocampal neurons. Two neighbouring cells display prominent immunoreactivity in the nuclei and immunoreactive puncta in dendrites. (B) Co-staining of endogenous muskelin (red) and synaptic vesicle protein SV2 (green). Yellow puncta represent apposition of muskelin and SV2-positive signals (arrows) indicative for synaptic localization of muskelin. Scale bars: 20 μm (A); 3 μm (B). (C) Western blot analysis of synaptosomes prepared from P10 rats. Detection of the synaptic markers PSD-95 and gephyrin confirms enrichment of excitatory and inhibitory synapses, respectively. Muskelin is detectable within synaptosomal fractions. (D) Detection of muskelin expression in cultured hippocampal neurons from different developmental stages (DIV3-DIV13). Actin detection serves as a loading control.