Real-Time Growth Kinetics Analysis of Macromolecular Assemblies in Cells with Single Molecule Resolution

Area of Science:

• Cell Biology
• Biophysics
• Microscopy Techniques

Background:

• Single molecule fluorescence microscopy enables real-time study of protein complex assembly in cellular membranes.
• Quantifying real-time assembly kinetics and stoichiometry of intracellular protein oligomers remains challenging.
• Existing methods lack efficient analysis for high-order oligomer formation at single-molecule resolution.

Purpose of the Study:

• To develop and validate an automated software for analyzing real-time assembly kinetics of individual high-order oligomer complexes.
• To provide a fast, user-friendly tool for tracing the compositional evolution of macromolecular assemblies in cells.
• To facilitate deeper understanding of the structural and biophysical mechanisms governing protein assembly functions.

Main Methods:

• Developed automated analysis software with a Graphical User Interface (GUI) for tracing real-time oligomer assembly.
• Software available as source code and executable for broad accessibility.
• Validated using simulated data and time-lapse images of BAX/BAK protein oligomers on mitochondria during apoptosis.

Main Results:

• The software accurately measures real-time assembly kinetics of individual high-order oligomers.
• Analysis of hundreds to thousands of molecules is completed in under 2 minutes.
• Demonstrated suitability for intracellular protein oligomers with variable signal detection.

Conclusions:

• The developed software offers a significant advancement for studying protein assembly dynamics at the single-molecule level.
• Provides biologists with a rapid and accessible tool to investigate macromolecular assembly processes.
• Enables quantitative analysis crucial for modeling and understanding the functional mechanisms of protein complexes.