Landscape expansion microscopy reveals interactions between membrane and phase-separated organelles

Area of Science:

• Cellular and Molecular Biology
• Microscopy Techniques
• Biophysics

Background:

• Superresolution microscopy is crucial for visualizing cellular ultrastructure.
• Existing expansion microscopy (ExM) methods face challenges in achieving high signal-to-noise ratios for both proteins and lipids.
• Understanding the spatial organization of membrane organelles and phase separations requires advanced imaging techniques.

Purpose of the Study:

• To introduce and validate Landscape expansion microscopy (land-ExM) for enhanced superresolution imaging.
• To overcome the signal-to-noise limitations of conventional ExM for simultaneous protein and lipid visualization.
• To enable detailed 3D visualization of organelle contact sites and phase separation interactions.

Main Methods:

• Development of land-ExM utilizing self-retention trifunctional anchors.
• Application of land-ExM to enhance protein and lipid signals in expanded biological samples.
• Imaging of diverse membrane organelles, phase separations, and their contact sites in 3D.

Main Results:

• land-ExM significantly enhances protein and lipid signals, achieving high contrast and superresolution.
• The technique allows accurate visualization of various membrane organelles and cellular phase separations.
• Demonstrated visualization of triple-organellar contact sites involving stress granules, nuclear tunnels, and nucleoli.

Conclusions:

• land-ExM provides a novel high-contrast superresolution platform for ultrastructural cell biology.
• This method advances the understanding of spatial coordination between membrane organelles and phase separations.
• land-ExM facilitates detailed investigation into the complex interactions within cellular compartments.