Src regulates distinct pathways for cell volume control through Vav and phospholipase Cgamma

Area of Science:

• Cell Biology
• Molecular Biology
• Biophysics

Background:

• Cell volume regulation is crucial for cellular integrity.
• Swelling-induced cell volume recovery involves cytoskeletal changes and ion channel activity.
• Phospholipase Cgamma (PLCgamma) and Rho GTPases are implicated in cellular responses to swelling.

Purpose of the Study:

• To investigate the role of Src kinase in mediating cellular responses to hypotonic swelling.
• To identify swelling-induced effectors of Src kinase.
• To understand how Src coordinates cytoskeletal reorganization and fluid efflux during cell volume recovery.

Main Methods:

• Utilized hypotonic challenge to induce cell swelling.
• Investigated Src kinase activation and localization using immunofluorescence.
• Assessed protein phosphorylation (Vav, PLCgamma) and ion channel activity.
• Employed Src inhibitor PP2 to evaluate its effects on cellular processes.

Main Results:

• Src kinase rapidly activated in plasma membrane protrusions upon hypotonic challenge.
• Src colocalized with Vav, a Rho GTPase activator, in these protrusions.
• Inhibition of Src by PP2 reduced Vav and PLCgamma phosphorylation.
• PP2 treatment inhibited swelling-mediated activation of K+ and Cl- channels and impaired cell volume recovery.

Conclusions:

• Swelling-induced Src kinase activation is a key regulator of cellular responses to osmotic stress.
• Src coordinates cytoskeletal dynamics via Vav and fluid efflux via PLCgamma.
• Src plays a critical role in maintaining cellular integrity during swelling by integrating structural and fluid balance mechanisms.