Active intracellular transport in metastatic cells studied by spatial light interference microscopy

Area of Science:

• Cell Biology
• Biophysics
• Microscopy

Background:

• Quantifying spatiotemporal patterns of intracellular transport remains challenging.
• Understanding the balance of random (passive) and directed (active) motion within cells is crucial.
• Existing data lacks broad spatiotemporal scale quantitative analysis.

Purpose of the Study:

• To quantitatively analyze intracellular transport dynamics in live cells.
• To differentiate between active and passive transport mechanisms in the cytoplasm and nucleus.
• To investigate the velocity distributions of mass transport during cell division.

Main Methods:

• Utilized spatial light interference microscopy (SLIM), a quantitative phase imaging technique.
• Performed long-term (30-hour) observation of 2D mass density in HeLa cells.
• Analyzed the active component of transport and velocity distributions.

Main Results:

• Intracellular transport is predominantly active in the cytoplasm.
• Transport within the nucleus exhibits both active and passive characteristics.
• Velocity distributions in the cytoplasm are broader than in the nucleus, indicating faster transport.

Conclusions:

• Spatial Light Interference Microscopy provides high spatiotemporal resolution for studying intracellular dynamics.
• Distinct transport mechanisms operate in the cytoplasm versus the nucleus.
• The broader velocity distribution in the cytoplasm suggests more efficient or rapid molecular and organelle movement compared to the nucleus.