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Biology subjects

Mund, M.

Publications and source records attributed to Mund, M..

3 recordsLinked to original sources

Topological data analysis quantifies biological nano-structure from single molecule localization microscopy

The study of complex molecular organisation and nano-structure by localization based microscopy is limited by the available analysis tools. We present a segmentation protocol which, through the application of persistence based clustering, is capable of probing densely packed structures which vary in scale. An increase in segmentation performance over state-of-the-art methods is demonstrated. Moreover we employ persistent homology to move beyond clustering, and quantify the topological structure within data. This provides new information about the preserved shapes formed by molecular architecture. Our methods are flexible and we demonstrate this by applying them to receptor clustering in platelets, nuclear pore components and endocytic proteins. Both 2D and 3D implementations are provided within RSMLM, an R package for pointillist based analysis and batch processing of localization microscopy data.

bioinformatics

Systematic analysis of the molecular architecture of endocytosis reveals a nanoscale actin nucleation template that drives efficient vesicle formation

Clathrin-mediated endocytosis is an essential cellular function in all eukaryotes that is driven by a self-assembled macromolecular machine of over 50 different proteins in tens to hundreds of copies. How these proteins are organized to produce endocytic vesicles with high precision and efficiency is not understood. Here, we developed high-throughput superresolution microscopy to reconstruct the nanoscale structural organization of 23 endocytic proteins from over 100,000 endocytic sites in yeast. We found that proteins assemble by radially-ordered recruitment according to function. WASP family proteins form a circular nano-scale template on the membrane to spatially control actin nucleation during vesicle formation. Mathematical modeling of actin polymerization showed that this WASP nano-template creates sufficient force for membrane invagination and substantially increases the efficiency of endocytosis. Such nanoscale pre-patterning of actin nucleation may represent a general design principle for directional force generation in membrane remodeling processes such as during cell migration and division.

cell biology

Fast, robust and precise 3D localization for arbitrary point spread functions

We present a fitter for 3D single-molecule localization of arbitrary, experimental point spread functions (PSFs) that reaches minimum uncertainty for EMCCD and sCMOS cameras, and achieves more than 105 fits/s. We provide tools to robustly model experimental PSFs and correct for depth induced aberrations, which allowed us to achieve an unprecedented 3D resolution with engineered astigmatic PSFs, and acquire high quality 3D superresolution images even on standard microscopes without 3D optics.

biophysics