Ubiquitination polymer (IMAGE) University of Chicago Caption In baker’s yeast, Ubr1 helps initiate the ubiquitination process as it attaches ubiquitin to proteins and elongates it into a chain of molecules known as a polymer. Credit Pan, et al, University of Chicago Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.