Role of mechanical flow for actin network organization

Area of Science:

• Cell Biology
• Biophysics
• Cytoskeletal Dynamics

Background:

• Actin networks provide cellular structure, primarily organized by actin-binding proteins (ABPs).
• The role of the mechanical cellular environment, specifically cytoplasmic flow, on actin network organization is understudied.
• Cellular shape changes occur rapidly, potentially influencing actin network formation during dynamic processes.

Purpose of the Study:

• To investigate the hypothesis that mechanical flows in the cytoplasm spatiotemporally regulate actin architecture.
• To determine how simulated cytoplasmic streaming affects the formation of actin networks with varying ABPs.
• To elucidate the interplay between mechanical forces and ABP crosslinking in determining actin network structure.

Main Methods:

• Generated circulating flow using surface acoustic waves in a microfluidic channel to mimic cytoplasmic streaming.
• Investigated the effects of this flow on actin and ABP network formation.
• Developed a computational model to analyze the forces governing actin bundle alignment and thickness.

Main Results:

• Mechanical flow significantly affected the orientation and thickness of actin bundles.
• The impact of flow varied depending on the type and concentration of ABPs used.
• Computational modeling revealed that flow-induced drag forces and ABP crosslinking angles dictate actin bundle characteristics.

Conclusions:

• Local intracellular flows play a crucial role in the assembly dynamics and morphology of the actin cytoskeleton.
• This finding advances the understanding of how mechanical cues contribute to actin network reorganization.
• Results are relevant for comprehending actin cytoskeleton dynamics in physiological and pathological cellular processes.