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Intracellular fluid flow in rapidly moving cells
Kinneret Keren1, Patricia T Yam, Anika Kinkhabwala
1Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA. kinneret@ph.technion.ac.il
Nature Cell Biology
|September 22, 2009
Summary
Cytosolic fluid dynamics drive cell movement. Forward fluid flow in fish keratocytes propels cell motility, influenced by myosin contraction and hydrostatic pressure.
Area of Science:
- Cell Biology
- Biophysics
- Mechanobiology
Background:
- Cytosolic fluid dynamics are crucial for cell motility, influencing component transport and generating hydrodynamic forces.
- Understanding fluid flow direction and mechanics in moving cells is key to elucidating motility mechanisms.
Purpose of the Study:
- To investigate the existence and direction of fluid flow within the lamellipodia of rapidly moving cells.
- To determine the relationship between fluid flow, cell speed, and underlying molecular mechanisms like myosin contraction.
Main Methods:
- Introduction of inert quantum dots into the lamellipodia of fish epithelial keratocytes to track fluid motion.
- Analysis of quantum dot distribution and motion to determine fluid flow velocity relative to cell speed.
- Inhibition of myosin II activity using blebbistatin to assess its effect on fluid flow and cell motility.
Main Results:
- Fluid flow was observed to be directed from the cell body towards the leading edge at approximately 40% of the cell's speed.
- Inhibition of myosin II activity with blebbistatin reversed the direction of fluid flow.
- Myosin II inhibition also resulted in a significant decrease in keratocyte speed.
Conclusions:
- Forward-directed cytosolic fluid flow, driven by myosin-generated hydrostatic pressure, is a key factor in keratocyte motility.
- Myosin II activity plays a critical role in generating the pressure gradient that drives forward fluid flow and maintains cell speed.
- A physical model was developed that quantitatively explains the observed fluid pressure and flow dynamics in moving cells.
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