Peter Agre /ˈɑːɡriː/ (born January 30, 1949) is an American physician, Bloomberg Distinguished Professor, and molecular biologist at Johns Hopkins University who was awarded the 2003 Nobel Prize in Chemistry (which he shared with Roderick MacKinnon) for his discovery of aquaporins. Aquaporins are water-channel proteins that move water molecules through the cell membrane. In 2009, Agre was elected president of the American Association for the Advancement of Science (AAAS).