In drosophila, the calcium channel flower (fwe) is a homomultimeric protein on the plasma membrane of cells that couples synaptic exocytosis with endocytosis, both processes being regulated by Ca2+. Influx of Ca2+, triggered by voltage-gated Ca2+ channels, is necessary for synaptic vesicle fusion with the plasma membrane. Drosophila fwe is able to mediate Ca2+ influx and thus regulate synaptic endocytosis. Fwe can form at least a dimer but also higher multimers (Yao et al. 2009). The function of human calcium channel flower homologue (CACFD1) is based on inference from functional drosophila fwe.