The project aimes to unravel the function of metacaspases in plants (and fungi and protozoans). To achieve this major goal, the project will pursue the following sub-objectives: 1. Detailed phenotypic and biochemical analysis of transgenic lines with perturbed AtMC9/4 (a type II metacaspase) levels. 2. Discovery of metacaspase inhibitors 3. Proteome-wide identification of protein substrates for AtMC9/4 4. Functional analysis of AtMC9/4 protein substrates.