Biomolecular Condensates Can Induce Local Membrane Potentials

Area of Science:

• Cell Biology
• Biophysics
• Biochemistry

Background:

• Biomolecular condensates are membrane-less cellular compartments crucial for biological processes.
• Condensates interact with lipid membranes in cellular functions like autophagy and T-cell activation.
• Surface charge and electric potential of condensates suggest a role in membrane interactions.

Purpose of the Study:

• To investigate if biomolecular condensates can alter local membrane potential.
• To explore the electrostatic mechanisms underlying condensate-membrane interactions.
• To understand the implications for cellular signaling.

Main Methods:

• Utilized a model system with poly-lysine (polyK)/adenosine triphosphate (ATP) coacervates and Giant Unilamellar Vesicles (GUVs).
• Employed an electrochromic dye to detect localized membrane potential changes.
• Performed numerical modeling using an electro-thermodynamic framework.

Main Results:

• PolyK/ATP coacervates were shown to induce localized membrane potential in GUVs.
• The observed effect decreased with higher salt concentrations and ATP-to-polyK ratios.
• Condensate charge and Galvani potential were identified as key factors influencing membrane potential.

Conclusions:

• Biomolecular condensate wetting of lipid membranes can locally alter membrane potential.
• This phenomenon is dependent on condensate electrostatic properties and environmental conditions.
• Findings suggest a novel regulatory role for condensate-membrane interactions in biological processes like neuronal signaling.