Rosen, R., Department of Molecular Microbiology and Biotechnology, George S Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Biran, D., Department of Molecular Microbiology and Biotechnology, George S Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Gur, E., Department of Molecular Microbiology and Biotechnology, George S Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Becher, D., Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany
Hecker, M., Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany
Ron, E.Z., Department of Molecular Microbiology and Biotechnology, George S Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel

Protein aggregation is involved in several human diseases, and presumed to be an important process in protein quality control. In bacteria, aggregation of proteins occurs during stress conditions, such as heat shock. We studied the protein aggregates of Escherichia coli during heat shock. Our results demonstrate that the concentration and diversity of proteins in the aggregates depend on the availability of proteases. Aggregates obtained from mutants in the Lon (La) protease contain three times more protein than wild-type aggregates and show the broadest protein diversity. The results support the assumption that protein aggregates are formed from partially unfolded proteins that were not refolded by chaperones or degraded by proteases. © 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.