PLCD1 and cancer: To better understand the structural implications of the cancer-associated mutations in DLC1-START and the role of these mutations in DLC1 interaction with PS, Caveolin-1, and PLCD1, we built a homology model of DLC1-START, using DLC2-START as a template for homology modeling, as its crystal structure, which has been reported [21], shares 57% sequence identity and 73% sequence similarity with DLC1-START (Supplementary Figure 7A).