Prof. Scott Emr, molecular biology, earned the 2021 Shaw Prize for Life Science and Medicine for unpacking the secrets of a set of proteins that are able to detect key molecular signals to transport proteins to their rightful homes in cells. The Emr lab discovered the function of the endosomal sorting complex required for transport proteins by deleting the genes responsible for the synthesis of the proteins that guide the formation of endosomal vesicles in yeast cells. “[Genetics allows us to] look into the darkness and ask the organism, tell me, how do you do this,” Emr said. In their most recent research, Emr and his colleagues described the recognition and coupling of the protein ubiquitin — a molecular switch that functions as a signal for recruiting vacuolar protein sorting genes — cellular United Postal Service and intiating membrane bending and pinching.
The experiment employed the fact that yeast digests its nutrients extracellularly through enzymes like invertase to process the sucrose in the growth medium into glucose and fructose — the energy currency in yeast. Emr fused invertase to carboxypeptidase, a protein that needs to be transported within the cell to the lysosome.