Stress-induced structural and organizational adaptations of the cellular translation machinery

Introduction

Many cellular and extracellular events cause perturbations of protein homeostasis by affecting either de novo protein folding or by destabilizing already folded proteins. Under such proteotoxic stress conditions, cells engage in various strategies to avoid further damage to the cellular proteome, e.g. by timely modulation of translation activity and specificity, or by resolving the underlying events.

Project Goals

Our overall goal is to dissect from a unique structural angle how such damage avoidance strategies impact the structure and molecular organization of the translation machinery. This will be achieved by:

1. Directly imaging their effects on ribosome structure.
2. Analyzing supramolecular organization.
3. Examining distribution in a cellular context with cryo-electron tomography (cryo-ET).

Cryo-ET is an innovative imaging approach unique in its capability to provide highly detailed three-dimensional structural information on macromolecular complexes in their cellular environment.

Methodology

Building on my pioneering work in the field of cryo-ET and integrating novel image processing solutions that have recently marked a breakthrough in the field, we will dissect at unprecedented resolution how the cellular translation machinery is remodeled:

i) After a general heat-shock,
ii) During the Endoplasmic Reticulum unfolded protein response, and
iii) During persistent translational stalling triggering ribosome-associated quality control.

Expected Outcomes

Work included in this proposal will provide detailed structural and mechanistic insights into how cells try to counteract an imbalance of protein homeostasis—a hallmark of neurodegenerative diseases.

It thus seems almost certain that key concepts emerging from our studies will have direct implications on the mechanistic understanding of central pathological principles underlying these diseases.