VPS35 and Parkinson disease: In the future, it will also be important to examine potential genetic interactions in other PD models, including LRRK2 transgenic flies or those containing mutations in other PD loci, such as VPS35 or parkin. While neuroblastoma cells offer the convenience of robust mitochondrial readouts, they are limited by their undifferentiated, transformed state distinct from that of postmitotic neurons.