The role of a Domain of Unknown Function (DUF) protein in chloroplast and mitochondrial retro-grade signalling pathways

Thylakoid membranes in chloroplasts are the location for the light-dependent reaction of photosynthesis, the
electron transport chain (ETC). We study a protein of unknown function, which is localised at the thylakoid
membrane and appears to be necessary for the regulation of ETC under starvation conditions. This protein
may be necessary to sense the energy status of the chloroplasts and transducing this signal to the nucleus,
but how this works is still unclear. We have recently identified potential intermediate proteins of this signalling
pathway, which we will investigate further through isolating chloroplast complexes involving the unknown
protein from plants.
Reactive oxygen species (ROS) are produced as a by-product of the electron transport chain in the
chloroplast, which can also act as a signal switching on gene expression in the nucleus. Plants that lack the
protein of unknown function have altered responses of genes encoding for mitochondrial and chloroplast
proteins under starvation conditions. We will use biochemical and genetic approaches to study the role of the
protein of unknown function in the production ROS in chloroplast and potentially mitochondria influencing the
expression of nuclear genes.