May have an important role in presynaptic function. Expressed in wide range of synaptic terminals: embryonic nervous system, larval neuromuscular junctions, adult visual system (neuropil of optic ganglia and terminal of R1-8 photoreceptors) and thoracic neuromuscular junctions. Also expressed in non-neuronal cells: follicle cells, spermatheca, testis and ejaculatory bulb. Low level of expression is found in many neuronal and non-neuronal tissues. Fatty acylated. Heavily palmitoylated in the cysteine string motif.