ABCG2 is a membrane transporter regulating the absorption and distribution of over 200 chemical toxins and drugs in the human body. Being able to recognize and transport a wide range of molecules, including a diverse array of chemotherapeutic agents, ABCG2 is one of the main contributors to multidrug resistance in cancer cells. In collaboration with Schuetz lab at St. Jude Children's Research Hospital, and using molecular simulations with NAMD and analyzed by VMD, we showed how a single-point mutation in ABCG2 found in tumor cells cannot complete its transport activity. Our simulations show that formation of a salt-bridge at a critical region due to the mutation may lock the transporter in one structure, thereby preventing it from undergoing conformational changes that are needed for transport. Read more in Drug Resistance Updates.