Mechanical behavior in living cells consistent with the tensegrity model

Area of Science:

• Cell Biology
• Biophysics
• Cytoskeletal Dynamics

Background:

• Existing cell mechanics models include continuum, gel, membrane, and tensegrity networks.
• Tensegrity models propose discrete elements bear compression to maintain prestress and stability.
• Understanding the mechanical behavior of living cells is crucial for cell biology and biophysics.

Purpose of the Study:

• To investigate the mechanical behavior of living cells under stress.
• To determine the role of microtubules and actin microfilaments in cellular mechanics.
• To evaluate the validity of the tensegrity model in explaining cell shape stability.

Main Methods:

• Real-time microscopic analysis of cells with GFP-labeled microtubules and mitochondria.
• Application of mechanical stresses to cell surface integrin receptors.
• Quantification of cell tractional forces and cellular prestress using traction force microscopy.

Main Results:

• Living cells behave as discrete structures of interconnected actin and microtubules under stress.
• Microtubules were confirmed to bear compression and contribute significantly to cytoskeletal prestress.
• Cellular prestress, independent of myosin light chain phosphorylation and intracellular calcium, dictates cell shape stability.
• Mechanical behaviors observed align with predictions of the tensegrity model.

Conclusions:

• The tensegrity model provides a unified framework for understanding cell mechanics.
• Collective interactions among cytoskeletal filaments and extracellular adhesions govern emergent mechanical behaviors.
• Microtubules play a critical role in maintaining cell shape stability through compression resistance.