“It’s been known for decades that proteins can be internalized from the cell boundary into cellular compartments known as endosomes,” says Yale’s Alanna Schepartz, Sterling Professor of Chemistry and professor of molecular, cellular & developmental biology. “Getting these molecules out of endosomes and into the cell interior was the big problem.”

Schepartz and colleagues at Yale now report the identity of a molecular key that effectively unlocks the endosome, allowing the selective passage into the cell interior of potentially life-saving protein drugs.