The calcium-dependent activator protein for secretion (CAPS) is an established priming factor for large dense core vesicles (LDCVs) and has been reported to prime synaptic vesicles (SVs) as well [1, 2]. It is a multi-domain protein consisting of two family members CAPS1 and CAPS2. Recently, we showed that in dorsal root ganglion (DRG) neurons CAPS1 exclusively mediates SV exocytosis, while CAPS2 only promote neuropeptide release from LDCVs. We further showed that their differential function is due to distinct localization. In fact, CAPS1 is highly enriched at synapses while CAPS2 has a more diffuse mainly somatic localization. To establish and maintain this differential localization, the subcellular transport mechanism of both CAPS paralogs must differ and be tightly controlled. In the peripheral nervous system, cell soma and synaptic contacts are separated by a great distance, which poses a challenge for synaptic targeting of cytoplasmic proteins. Active zone proteins overcome this problem by their association with so-called piccolo/bassoon transport vesicles. We propose that CAPS1 but not CAPS2 is able to bind to these vesicles to be directed to synapses. We investigated this question by targeted mutagenesis of CAPS2. We verified that our mutant CAPS2/CAPS1 was correctly expressed and functional. Using immunocytochemistry together with confocal microscopy we could show that the CAPS2/CAPS1 chimera protein was re-localized from the soma to synapses (Fig. 1). With this approach we identified a specific domain responsible for CAPS1 synaptic localization.