Shell tension forces propel Dictyostelium slugs forward.

Area of Science:

• Cellular and Molecular Biology
• Biophysics
• Developmental Biology

Background:

• The Dictyostelium slug is a model organism for collective cell migration.
• The physical mechanisms driving slug movement are not fully understood.

Purpose of the Study:

• To investigate the physical mechanisms behind Dictyostelium slug propulsion.
• To explain how collective cell movement is achieved in this model system.

Main Methods:

• Utilized a recently developed 3D traction force microscopy technique.
• Analyzed forces exerted by the surrounding cellular sheath.

Main Results:

• Identified the surrounding sheath as the primary source of propulsive forces.
• Quantified the uniform tension of the sheath (approximately 50 mN m(-1)).
• Demonstrated that sheath tension creates internal tissue pressure.

Conclusions:

• Slug propulsion is driven by internal pressure generated by a tense sheath.
• A gradient in the mechanical properties of the anterior sheath likely directs forward movement.