Proteostasis (protein homeostasis) is essential for keeping the proteome functional. This process controls protein synthesis, folding and degradation and involves hundreds of genes, including those encoding chaperones, to form extensive quality control (QC) networks1. Imbalances in proteostasis are implicated in a range of aggregation-based neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS), Huntington’s and Alzheimer’s diseases2,3. Currently there is a lack of capacity to quantitatively measure proteostasis imbalance and therefore we are limited in understanding how proteostasis imbalance manifests during disease. We have generated a new biosensor system to address this shortfall. The biosensor is a genetically encoded unfolded “bait” flanked by two fluorescent proteins to assay foldedness by fluorescence resonance energy transfer. Proteostasis efficiency is reported by measurement of the efficiency to which the bait interacts with the QC. We report here how this biosensor works and ongoing projects to focus the biosensor into discrete intracellular locations and in a nematode whole animal model for probing organismal and aging-related changes in proteostasis.