Cytoplasmic stirring by active carpets.

Area of Science:

• Cell Biology
• Biophysics
• Fluid Dynamics

Background:

• Large cells utilize cytoplasmic flows for essential functions like transport and homeostasis.
• Understanding these flows is crucial for cell biology, development, and evolution.
• Cortex-based fluid-structure interactions drive self-organized cytoplasmic stirring.

Purpose of the Study:

• To propose an analytically tractable active carpet theory for self-organized cytoplasmic flows.
• To decipher the origins and 3D spatiotemporal organization of these flows.
• To model fluid-structure interactions between cytoskeletal elements at the cell cortex.

Main Methods:

• Developed an active carpet theory inspired by fruit fly oocyte streaming flows.
• Employed computational simulations to analyze flow dynamics.
• Utilized weakly nonlinear theory to understand flow organization.

Main Results:

• Established the pathway of streaming flow to a global attractor: a cell-spanning vortical twister.
• Revealed inherent symmetries and low-dimensional structure of the emergent flow.
• Demonstrated alignment of complex fluid-structure interactions with classical Stokes flow solutions.

Conclusions:

• The active carpet theory provides a framework for understanding cortex-driven intracellular flows.
• The model elucidates the emergence of complex, self-organized flows from simple interactions.
• This adaptable framework can be applied to diverse self-organized, cortex-driven intracellular flow systems.