Historically, a central paradigm in cellular organisation is that the cell is compartmentalised into functionally specialised membrane-bound organelles such as the nucleus, mitochondria, lysosomes and vacuoles.
However, in recent years it has been shown across all branches of life that another important form of compartmentalisation can occur. This happens through de-mixing of previously soluble cellular components that condense out into protein rich liquid droplets. These droplets called biomolecular condensates are like mini reaction-chambers and have specialised biological functions in normal cells. Many age-related neurological diseases such as ALS are associated with pathological hardening of liquid condensates to form solid aggregates. What is needed for better understanding of condensate formation and developing novel therapeutic approaches is a way to accurately measure within a living cell, a healthy condensate versus one tending towards pathological hardening.
We address this knowledge gap through an exciting and timely interdisciplinary project involving an internationally recognised team of molecular cell biologists, computational biologists, soft matter physicists and neurobiologists. FlickerPRINT employs Flicker Spectroscopy to measure the characteristic flicker or ‘wobble’ associated with a liquid droplet versus a more viscous droplet or gel, i.e. the ‘fingerprint’ of a healthy liquid condensate versus one tending towards pathological hardening, for example by comparing normal cells with those carrying ALS mutations. Our ambition is to be able to profile condensates based on their material properties and relate it to disease-specific changes in condensate profiles.
FlickerPRINT employs Flicker Spectroscopy (FS) to obtain quantitative information on the material state of liquid-droplet organelles, also called biomolecular condensates. Many neurological diseases are associated with pathological hardening of liquid-droplet organelles to form solid fibrillar aggregates. FS exploits the shape fluctuation information (flicker) of liquid droplets to quantify subtle changes in its mechanical properties like surface tension, bending rigidity and viscosity due to changes in material state. Since condensates are dynamic and typically composed of hundreds of proteins and RNA species, listing their composition using current high throughput molecular techniques is of limited value for predicting the likelihood of transition from liquid to solid. What is needed for mechanistic understanding and therapeutic approaches, is a way to measure with high spatial and temporal resolution in-situ within a living cell, the characteristic ‘fingerprint’ of a healthy liquid condensate versus one tending towards pathological hardening. FlickerPRINT addresses this knowledge gap through an exciting and timely interdisciplinary project. Our team of molecular cell biologists, computational biologists, soft matter physicists and neurobiologists aim to tackle a key question in life sciences, namely: How do changes in protein composition of condensates manifest as a change in condensate material state and dysregulated function? We have recently developed a novel condensate FS method that we will benchmark rigorously in this study using modular tunable systems that generate a range of condensate types. It is this combination that makes this proposal timely and makes us uniquely placed to deliver this program. Our ambition is to be able to profile condensates based on their material properties and relate it to disease-specific changes in condensate profiles.