Force sensing and generation in cell phases: analyses of complex functions

Area of Science:

• Cell Biology
• Biophysics
• Developmental Biology

Background:

• Cellular morphology is governed by dynamic processes like motility, force sensing, and generation, integrated with the cytoskeleton and extracellular matrix.
• Protein expression variations during cell differentiation drive morphological changes.
• Two models explain cell motility: continuous dependence on composition or phased activation of specific protein modules.

Purpose of the Study:

• To investigate the phased nature of cell motility and its underlying mechanisms.
• To understand how distinct cellular behaviors transition between phases.
• To elucidate the role of force sensing and protein activity in driving morphological changes.

Main Methods:

• Quantification of cell spreading and motile activities.
• Observation of transitions between different cellular behaviors (phases).
• Analysis of protein activities corresponding to distinct motile phases.

Main Results:

• Cellular motility exhibits distinct, abrupt transitions between phases, supporting a model of localized protein module activation.
• Cells transition from basal motility in suspension to activated spreading upon surface contact.
• Subsequent phases involve substrate rigidity sensing through contraction and force development, followed by decreased extension and focal complex assembly.

Conclusions:

• Cellular morphology is regulated by discrete motile phases, each characterized by specific protein activities and functions.
• Tissue-wide morphological changes result from chemical signals and force-dependent activation of these localized, time-defined motile phases.