Specialized iNANO Lecture: Chaperone-protease complexes in cell development and regulation

Prof. Kürsat Turgay, Department of Microbiology, Leibniz University Hannover, Germany

Chaperone-protease complexes in cell development and regulation

General and regulatory proteolysis is an important part of different cellular processes such as protein homeostasis and the specific control of regulatory networks for cellular development or stress response in the Gram+ model organism Bacillus subtilis. The intricate involvement of AAA+ proteins and their adaptor proteins in these processes are introduced and discussed.

We investigated the thermotolerance development by analyzing cell survival, in vivo protein aggregate formation and transcriptome changes in severely heat shocked cells of wild type and mutant strains primed by a mild heat shock. In these experiments we could identify the thiol stress regulator Spx as an important and central heat shock regulator in B. subtilis stress response system. We also observed a strong down-regulation of genes e.g. for ribosome biogenesis and translation known to be stringent response controlled.

Our results suggest that B. subtilis cells respond to heat mediated protein unfolding and aggregation not only by raising the cellular repair capacity (e.g. more (redox) chaperones) but also by decreasing translation involving (p)ppGpp, RelA and Spx mediated response to concurrently reduce the load for the cellular protein quality control system.

Host: Ümit Akbey, Ph.D. Assistant Professor, iNANO  & AIAS COFUND Fellow