Synthetic biology is currently undergoing a transition from a design‐driven era of creating template circuits into a demand‐driven discipline focused on the creation of problem‐solving cell functions.[47, 48, 49] By engineering synthetic gene circuits customized to quantify CaV1.2 and CaV1.3 activities individually, we were able to overcome a major technical obstacle to drug discovery for PD. The gene discussed is CACNA1D; the disease is Parkinson disease.