To guard the cell interior against pathogens and other insults, it is vital that our cells meet threats with a targeted and swift response. For intracellular membrane compartments like endosomes, lysosomes and phagosomes a key response is the process called “Conjugation of ATG8 proteins to Single Membranes” (CASM). This membrane attachment of ATG8 proteins provides
a transient protein-docking platform to scaffold protective countermeasures.
Importantly, defects in CASM compromises our defense against pathogens and makes us susceptible to autoimmune disease. However, the mechanisms and processes through which CASM prevents these pathological conditions remain unknown.
This project aims to expand our understanding of how CASM “DETECT” harmful insults and to unveil the countermeasures CASM initiates in order to “PROTECT” the cell and prevent potential pathological conditions. Potentially this can provide insight into the role of CASM in response to infections and in preventing autoimmune disease, having both a scientific and a clinical impact.
Membrane compartments within the cell are exposed to different kinds of stress (e.g. pathogenic insults). Meeting stress-inducing agents with a swift response is key to minimize harmful effects. One such response is single membrane ATG8 conjugation (SMAC), where ATG8 proteins are attached to the surface of the compromised compartment. This provides a transient docking platform for proteins involved in protective countermeasures.
In this project I aim to characterize the machinery that mediates ATG8 conjugation on compromised endolysosomes. In Work Package 1 (WP1) I aim to characterize the targeting mechanism of the ATG8 conjugation machinery. Furthermore, by conducting an unbiased image based siRNA screen (WP2) I aim to identify additional machinery components involved in the SMAC pathway. As ATG8 conjugation on membranes provides a docking platform for other proteins, I also aim to identify such SMAC specific effector proteins using a proteomics approach. The identified proteins will be categorized according to function in order to understand which SMAC dependent countermeasures are initiated on compromised membranes (WP3). In WP4 we set out to mechanistically characterize the candidate proteins identified in WP2 and WP3 in further detail.