QuantiTrack: A unified software to study protein dynamics in living cells.

Area of Science:

• Cellular and Molecular Biology
• Biophysics
• Systems Biology

Background:

• Understanding protein spatiotemporal dynamics in live cells is crucial for linking molecular behavior to physiological functions.
• Single molecule tracking (SMT) is a powerful technique for studying protein dynamics at the single-molecule level.
• Current SMT analysis methods often require advanced programming skills and lack integration, hindering accessibility.

Purpose of the Study:

• To develop a user-friendly, end-to-end software solution for SMT analysis.
• To provide comprehensive analysis tools with quality control metrics for robust quantification of protein dynamics.
• To investigate the impact of hormone washout on glucocorticoid receptor (GR) dynamics and its target gene regulation.

Main Methods:

• Development of QuantiTrack, a MATLAB-based software with a graphical user interface for SMT analysis.
• Implementation of movie loading, single molecule tracking, and diverse analytical modules within QuantiTrack.
• Application of QuantiTrack to study Halo-tagged GR (Halo-GR) dynamics in response to hormone treatment and washout.

Main Results:

• QuantiTrack enables seamless SMT analysis from movie input to comprehensive data interpretation.
• Hormone washout leads to rapid downregulation of GR target genes.
• Analysis of Halo-GR dynamics revealed a reduced bound fraction, decreased occupancy in the activated mobility state, and shorter dwell times upon hormone washout.

Conclusions:

• QuantiTrack offers a convenient and accessible platform for advanced SMT analysis, empowering biologists.
• The software facilitates the investigation of complex protein dynamics, such as GR behavior under hormonal influence.
• This work demonstrates the utility of QuantiTrack in elucidating the molecular mechanisms underlying hormone-regulated gene expression.