Passive transport of Ca2+ ions through lipid bilayers imaged by widefield second harmonic microscopy.
Biophys J
; 122(4): 624-631, 2023 02 21.
Article
in En
| MEDLINE
| ID: mdl-36659849
ABSTRACT
In biology, release of Ca2+ ions in the cytosol is essential to trigger or control many cell functions. Calcium signaling acutely depends on lipid membrane permeability to Ca2+. For proper understanding of membrane permeability to Ca2+, both membrane hydration and the structure of the hydrophobic core must be taken into account. Here, we vary the hydrophobic core of bilayer membranes and observe different types of behavior in high-throughput wide-field second harmonic imaging. Ca2+ translocation is observed through mono-unsaturated (DOPCDOPA) membranes, reduced upon the addition of cholesterol, and completely inhibited for branched (DPhPCDPhPA) and poly-unsaturated (SLPCSLPA) lipid membranes. We propose, using molecular dynamics simulations, that ion transport occurs through ion-induced transient pores, which requires nonequilibrium membrane restructuring. This results in different rates at different locations and suggests that the hydrophobic structure of lipids plays a much more sophisticated regulating role than previously thought.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Second Harmonic Generation Microscopy
/
Lipid Bilayers
Language:
En
Journal:
Biophys J
Year:
2023
Document type:
Article
Affiliation country:
Suiza