The Weissman Lab solved the mystery of the function of MTCH2, a mitochondrial protein implicated in many diseases, including cancer. In a study published in Science, researchers found that MTCH2 acts as a funnel, shuttling various proteins (including those involved in programmed cell death) from the cytoplasm into the mitochondrial membrane. By introducing a mutation that makes MTCH2 more “greedy,” researchers made leukemia cells more sensitive to a cancer treatment.