Calcium-mediated actin reset (CaAR) mediates acute cell adaptations.

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Actin's role in cellular morphogenesis is established, but its dynamic equilibrium regulation under acute signaling remains unclear.
• Understanding how cells maintain actin balance during rapid responses is critical for cell function.

Purpose of the Study:

• To characterize a rapid and transient actin reset mechanism triggered by increased intracellular calcium levels.
• To investigate the role of Calcium-mediated actin reset (CaAR) in cellular adaptation.

Main Methods:

• Investigated rapid changes in actin polymerization and disassembly using live-cell imaging.
• Stimulated actin reset via calcium influx and monitored cellular responses.

Main Results:

• Identified Calcium-mediated actin reset (CaAR) as a rapid, transient process involving INF2-mediated actin polymerization at the ER and cortical actin disassembly.
• CaAR occurs across mammalian cell types in response to various physiological cues.
• Observed CaAR's effects on organelle immobilization, cell cortex repair, cell spreading, wound healing, and gene expression.

Conclusions:

• CaAR is a fundamental mechanism facilitating cellular adaptation to acute signals and stress.
• This process dynamically reorganizes actin, impacting cellular processes from organelle dynamics to gene expression.