Subcellular Lipid Atlas: Decoding Organelle Identity with Targeted Lipid Profiling

Organelle identity, defined by membrane and protein composition, is crucial for maintaining cellular organisation, functions and communication pathways. Disruption of organelle identity can lead to cellular dysfunction and severe health issues, such as fatty liver disease, cardiovascular diseases and lipid storage disorders. Although it is known that lipids are a hallmark of membrane identity, we still have a limited understanding of organellar lipid compositions. Particularly since lipids are very dynamic through transbilayer movement, local metabolism and lipid transfer between organelles, which requires a high temporal resolution to capture. While existing methods are effective for protein analysis, lipid profiling at the organelle level remains challenging.To answer the outstanding question of how organellar lipidomes shape organelle function, we propose an innovative chemical biology approach for organelle-specific lipid profiling. We will label the lipids of individual organelle membranes in vivo and determine their chemical identity and concentration by lipidomic profiling. We will first design and synthesise functionalised lipid probes for distinct organelles, allowing for their release and photo-crosslinking to endogenous lipids. By analysing the labelled lipids, we will acquire a precise and detailed lipid profiles of individual organelles, and furthermore characterise the lipidome of specific suborganellar membrane domains. This will allow us to define the organelle membrane identity of the major organelles with unprecedented spatial and chemical resolution. Such data will provide the much-needed basis to connect organelle identity and maintenance with function and the research community with open access, high-resolution lipid maps. This has the potential to change the way we think about biological membranes on a fundamental level, advancing not only our understanding of organelle function, but setting the stage to study its impact on health and disease.