During the aging process of an organism, there is a gradual loss of cellular protein quality control. This results in the increased production of toxic protein clumps, so-called aggregates. Using a comprehensive approach, researchers in the teams of F.-Ulrich Hartl and Matthias Mann at the MPIB now analyzed the changes in protein composition during aging. The results published in the journal Cell show that the quantitative proportions of proteins undergo a severe shift in the course of a lifetime. This also sheds new light on the origin and function of protein aggregates. “These findings demonstrate that the cells specifically accumulate chaperone-rich protein aggregates as a safety mechanism. Therefore, the aggregates seem to be an important part of healthy aging”, the scientists explain. The study also involved the groups of Michele Vendruscolo and Chris Dobson in Cambridge and of Richard Morimoto in Chicago.